FN3

Fibronectin type 3 domain

• SMART accession number: SM00060
• Description: One of three types of internal repeat within the plasma protein, fibronectin. The tenth fibronectin type III repeat contains a RGD cell recognition sequence in a flexible loop between 2 strands. Type III modules are present in both extracellular and intracellular proteins.
• Interpro abstract (IPR003961):

  Fibronectin is a dimeric glycoprotein composed of disulfide-linked subunits with a molecular weight of 220-250kDa each. It is involved in cell adhesion, cell morphology, thrombosis, cell migration, and embryonic differentiation. Fibronectin is a modular protein composed of homologous repeats of three prototypical types of domains known as types I, II, and III [ (PUBMED:6218503) ].

  Fibronectin type-III (FN3) repeats are both the largest and the most common of the fibronectin subdomains. Domains homologous to FN3 repeats have been found in various animal protein families including other extracellular-matrix molecules, cell-surface receptors, enzymes, and muscle proteins [ (PUBMED:1409594) ]. Structures of individual FN3 domains have revealed a conserved beta sandwich fold with one beta sheet containing four strands and the other sheet containing three strands (see for example {PDB:1TEN}) [ (PUBMED:1279805) ]. This fold is topologically very similar to that of Ig-like domains, with a notable difference being the lack of a conserved disulfide bond in FN3 domains. Distinctive hydrophobic core packing and the lack of detectable sequence homology between immunoglobulin and FN3 domains suggest, however, that these domains are not evolutionarily related [ (PUBMED:1279805) ].

  FN3 exhibits functional as well as structural modularity. Sites of interaction with other molecules have been mapped to short stretch of amino acids such as the Arg-Gly-Asp (RGD) sequence found in various FN3 domains. The RGD sequences is involved in interactions with integrin. Small peptides containing the RGD sequence can modulate a variety of cell adhesion invents associated with thrombosis, inflammation, and tumor metastasis. These properties have led to the investigation of RGD peptides and RGD peptide analogs as potential therapeutic agents [ (PUBMED:8548820) ].

• GO function: protein binding (GO:0005515)

There are 647694 FN3 domains in 183810 proteins in SMART's nrdb database.

Literature (relevant references for this domain)

Primary literature is listed below; Automatically-derived, secondary literature is also avaliable.

• Leahy DJ, Aukhil I, Erickson HP
• 2.0 A crystal structure of a four-domain segment of human fibronectin encompassing the RGD loop and synergy region.
• Cell. 1996; 84: 155-64

We have determined the 2.0 A crystal structure of a fragment of human fibronectin encompassing the seventh through the RGD-containing tenth type III repeats (FN7-10). The structure reveals an extended rod-like molecule with a long axis of approximately 140 A and highly variable relationships between adjacent domains. An unusually small rotation between domains 9 and 10 creates a distinctive binding site, in which the RGD loop from domain 10 and the "synergy" region from domain 9 are on the same face of FN7-10 and thus easily accessible to a single integrin molecule. The cell-binding RGD loop is well-ordered in this structure and extends approximately 10 A away from the FN7-10 core.

• Huber AH, Wang YM, Bieber AJ, Bjorkman PJ
• Crystal structure of tandem type III fibronectin domains from Drosophila neuroglian at 2.0 A.
• Neuron. 1994; 12: 717-31

We report the crystal structure of two adjacent fibronectin type III repeats from the Drosophila neural cell adhesion molecule neuroglian. Each domain consists of two antiparallel beta sheets and is folded topologically identically to single fibronectin type III domains from the extracellular matrix proteins tenascin and fibronectin. beta bulges and left-handed polyproline II helices disrupt the regular beta sheet structure of both neuroglian domains. The hydrophobic interdomain interface includes a metal-binding site, presumably involved in stabilizing the relative orientation between domains and predicted by sequence comparision to be present in the vertebrate homolog molecule L1. The neuroglian domains are related by a near perfect 2-fold screw axis along the longest molecular dimension. Using this relationship, a model for arrays of tandem fibronectin type III repeats in neuroglian and other molecules is proposed.

• Potts JR, Campbell ID
• Fibronectin structure and assembly.
• Curr Opin Cell Biol. 1994; 6: 648-55

Significant progress has been made recently in the determination of the structure and assembly of the important matrix protein fibronectin, a molecule mainly constructed from three modular units denoted Fn1, Fn2 and Fn3. Atomic resolution structures are now available for all three single modules, for Fn1 and Fn3 module pairs, and for the disulphide-linked join between fibronectin monomers. Combined with results from new binding and mutation studies, the new structural information is leading to a clearer view of structure/function relationships in intact fibronectin.

• Skorstengaard K, Holtet TL, Etzerodt M, Thogersen HC
• Collagen-binding recombinant fibronectin fragments containing type II domains.
• FEBS Lett. 1994; 343: 47-50

Each of the two type II domains and four larger fragments, containing one or two type II domains of fibronectin, have been expressed in Escherichia coli. A special vector, containing a fragment encoding the cleavage site for Factor Xa, Ile-Glu-Gly-Arg, inserted immediately before the protein fragment of interest, was used. After treatment of the purified fusion proteins with reduced/oxidized glutathione, the correctly folded fibronectin fragments were released by proteolytic digestion with Factor Xa. The largest fragment, consisting of two type II and two type I domains, was the only fragment able to bind to immobilized gelatin.

• Leahy DJ, Hendrickson WA, Aukhil I, Erickson HP
• Structure of a fibronectin type III domain from tenascin phased by MAD analysis of the selenomethionyl protein.
• Science. 1992; 258: 987-91

Fibronectin type III domains are found in many different proteins including cell surface receptors and cell adhesion molecules. The crystal structure of one such domain from the extracellular matrix protein tenascin was determined. The structure was solved by multiwavelength anomalous diffraction (MAD) phasing of the selenomethionyl protein and has been refined to 1.8 angstrom resolution. The folding topology of this domain is identical to that of the extracellular domains of the human growth hormone receptor, the second domain of CD4, and PapD. Although distinct, this topology is similar to that of immunoglobulin constant domains. An Arg-Gly-Asp (RGD) sequence that can function for cell adhesion is found in a tight turn on an exposed loop.

• Main AL, Harvey TS, Baron M, Boyd J, Campbell ID
• The three-dimensional structure of the tenth type III module of fibronectin: an insight into RGD-mediated interactions.
• Cell. 1992; 71: 671-8

The solution structure of the tenth type III module of fibronectin has been determined using nuclear magnetic resonance techniques. The molecule has a fold similar to that of immunoglobulin domains, with seven beta strands forming two antiparallel beta sheets, which pack against each other. Both beta sheets contribute conserved hydrophobic residues to a compact core. The topology is more similar to that of domain 2 of CD4, PapD, and the extracellular domain of the human growth hormone receptor than to that of immunoglobulin C domains. The module contains an Arg-Gly-Asp sequence known to be involved in cell adhesion. This tripeptide is solvent exposed and lies on a conformationally mobile loop between strands F and G, consistent with its cell adhesion function.

• Petersen TE et al.
• Partial primary structure of bovine plasma fibronectin: three types of internal homology.
• Proc Natl Acad Sci U S A. 1983; 80: 137-41

• Balian G, Click EM, Bornstein P
• Location of a collagen-binding domain in fibronectin.
• J Biol Chem. 1980; 255: 3234-6

Preferential labeling of COOH-terminal sequences in newly synthesized fibronectin was achieved by short term incorporation of radiolabeled amino acids in the presence of pactamycin, an inhibitor of polypeptide chain initiation. The labeled fibronectin was then cleaved with cathepsin D under conditions that yield a large (137,000-dalton) fragment that lacks collagen-binding properties, and a smaller (72,000-dalton) fragment that retains the ability of fibronectin to bind to collagen. Determination of the relative specific radioactivities of the two fragments leads us to conclude that the collagen-binding domain in fibronectin is located in the NH2-terminal third of the polypeptide chain and not in a COOH-terminal region as previously indicated by other structural studies.

Disease (disease genes where sequence variants are found in this domain)

SwissProt sequences and OMIM curated human diseases associated with missense mutations within the FN3 domain.

Protein	Disease
Anosmin-1 (P23352) (SMART)	OMIM:308700: Kallmann syndrome
Neural cell adhesion molecule L1 (P32004) (SMART)	OMIM:308840: Hydrocephalus due to aqueductal stenosis OMIM:307000: MASA syndrome OMIM:303350: Spastic paraplegia OMIM:312900:
Collagen alpha-1(VII) chain (Q02388) (SMART)	OMIM:120120: Epidermolysis bullosa dystrophica, dominant OMIM:131750: Epidermolysis bullosa dystrophica, recessive OMIM:226600: Epidermolysis bullosa, pretibial, dominant and recessive OMIM:131850:
Leptin receptor (P48357) (SMART)	OMIM:601007: LEPTIN RECEPTOR; LEPR
Cytokine receptor common subunit gamma (P31785) (SMART)	OMIM:308380: Severe combined immunodeficiency, X-linked OMIM:300400: Combined immunodeficiency, X-linked, moderate OMIM:312863:
Integrin beta-4 (P16144) (SMART)	OMIM:147557: Epidermolysis bullosa, junctional, with pyloric atresia OMIM:226730: Epidermolysis bullosa, generalized atrophic benign OMIM:226650:
Insulin receptor (P06213) (SMART)	OMIM:147670: Leprechaunism OMIM:246200: Rabson-Mendenhall syndrome OMIM:262190: Diabetes mellitus, insulin-resistant, with acanthosis nigricans

Metabolism (metabolic pathways involving proteins which contain this domain)

% proteins involved	KEGG pathway ID	Description
21.19	map04060	Cytokine-cytokine receptor interaction
13.17	map04360	Axon guidance
8.71	map04514	Cell adhesion molecules (CAMs)
7.56	map04510	Focal adhesion
5.15	map04512	ECM-receptor interaction
5.15	map04640	Hematopoietic cell lineage
4.81	map04520	Adherens junction
3.21	map04810	Regulation of actin cytoskeleton
2.75	map00530	Aminosugars metabolism
2.63	map04080	Neuroactive ligand-receptor interaction
1.72	map05210	Colorectal cancer
1.72	map04650	Natural killer cell mediated cytotoxicity
1.60	map04910	Insulin signaling pathway
1.60	map05215	Prostate cancer
1.15	map05214	Glioma
1.15	map04620	Toll-like receptor signaling pathway
1.15	map04730	Long-term depression
1.15	map05218	Melanoma
1.15	map04914	Progesterone-mediated oocyte maturation
1.03	map04920	Adipocytokine signaling pathway
1.03	map04020	Calcium signaling pathway
0.92	map05222	Small cell lung cancer
0.92	map05120	Epithelial cell signaling in Helicobacter pylori infection
0.92	map05050	Dentatorubropallidoluysian atrophy (DRPLA)
0.92	map04210	Apoptosis
0.92	map04930	Type II diabetes mellitus
0.80	map04120	Ubiquitin mediated proteolysis
0.80	map04660	T cell receptor signaling pathway
0.57	map00500	Starch and sucrose metabolism
0.46	map00361	gamma-Hexachlorocyclohexane degradation
0.34	map04740	Olfactory transduction
0.34	map00790	Folate biosynthesis
0.34	map02020	Two-component system - General
0.34	map00511	N-Glycan degradation
0.34	map01032	Glycan structures - degradation
0.23	map00531	Glycosaminoglycan degradation
0.23	map04010	MAPK signaling pathway
0.23	map04940	Type I diabetes mellitus
0.23	map00604	Glycosphingolipid biosynthesis - ganglioseries
0.23	map00600	Sphingolipid metabolism
0.11	map00603	Glycosphingolipid biosynthesis - globoseries
0.11	map00780	Biotin metabolism
0.11	map00740	Riboflavin metabolism
0.11	map00300	Lysine biosynthesis
0.11	map00310	Lysine degradation
0.11	map00561	Glycerolipid metabolism
0.11	map00052	Galactose metabolism
0.11	map02010	ABC transporters - General
0.11	map00520	Nucleotide sugars metabolism
0.11	map00550	Peptidoglycan biosynthesis

This information is based on mapping of SMART genomic protein database to KEGG orthologous groups. Percentage points are related to the number of proteins with FN3 domain which could be assigned to a KEGG orthologous group, and not all proteins containing FN3 domain. Please note that proteins can be included in multiple pathways, ie. the numbers above will not always add up to 100%.

Structure (3D structures containing this domain)

3D Structures of FN3 domains in PDB

PDB code	Title
1a22	HUMAN GROWTH HORMONE BOUND TO SINGLE RECEPTOR
1axi	STRUCTURAL PLASTICITY AT THE HGH:HGHBP INTERFACE
1bj8	THIRD N-TERMINAL DOMAIN OF GP130, NMR, MINIMIZED AVERAGE STRUCTURE
1bp3	THE XRAY STRUCTURE OF A GROWTH HORMONE-PROLACTIN RECEPTOR COMPLEX
1bpv	TITIN MODULE A71 FROM HUMAN CARDIAC MUSCLE, NMR, 50 STRUCTURES
1bqu	CYTOKYNE-BINDING REGION OF GP130
1c8p	NMR STRUCTURE OF THE LIGAND BINDING DOMAIN OF THE COMMON BETA-CHAIN IN THE GM-CSF, IL-3 AND IL-5 RECEPTORS
1cfb	CRYSTAL STRUCTURE OF TANDEM TYPE III FIBRONECTIN DOMAINS FROM DROSOPHILA NEUROGLIAN AT 2.0 ANGSTROMS
1cn4	ERYTHROPOIETIN COMPLEXED WITH EXTRACELLULAR DOMAINS OF ERYTHROPOIETIN RECEPTOR
1eba	COMPLEX BETWEEN THE EXTRACELLULAR DOMAIN OF ERYTHROPOIETIN (EPO) RECEPTOR [EBP] AND AN INACTIVE PEPTIDE [EMP33] CONTAINS 3,5-DIBROMOTYROSINE IN POSITION 4 (DENOTED DBY)
1ebp	COMPLEX BETWEEN THE EXTRACELLULAR DOMAIN OF ERYTHROPOIETIN (EPO) RECEPTOR [EBP] AND AN AGONIST PEPTIDE [EMP1]
1eer	CRYSTAL STRUCTURE OF HUMAN ERYTHROPOIETIN COMPLEXED TO ITS RECEPTOR AT 1.9 ANGSTROMS
1egj	DOMAIN 4 OF THE BETA COMMON CHAIN IN COMPLEX WITH AN ANTIBODY
1ern	NATIVE STRUCTURE OF THE EXTRACELLULAR DOMAIN OF ERYTHROPOIETIN (EPO) RECEPTOR [EBP]
1f6f	CRYSTAL STRUCTURE OF THE TERNARY COMPLEX BETWEEN OVINE PLACENTAL LACTOGEN AND THE EXTRACELLULAR DOMAIN OF THE RAT PROLACTIN RECEPTOR
1fna	CRYSTAL STRUCTURE OF THE TENTH TYPE III CELL ADHESION MODULE OF HUMAN FIBRONECTIN
1fnf	FRAGMENT OF HUMAN FIBRONECTIN ENCOMPASSING TYPE-III REPEATS 7 THROUGH 10
1fnh	CRYSTAL STRUCTURE OF HEPARIN AND INTEGRIN BINDING SEGMENT OF HUMAN FIBRONECTIN
1gh7	CRYSTAL STRUCTURE OF THE COMPLETE EXTRACELLULAR DOMAIN OF THE BETA-COMMON RECEPTOR OF IL-3, IL-5, AND GM-CSF
1hwg	1:2 COMPLEX OF HUMAN GROWTH HORMONE WITH ITS SOLUBLE BINDING PROTEIN
1hwh	1:1 COMPLEX OF HUMAN GROWTH HORMONE MUTANT G120R WITH ITS SOLUBLE BINDING PROTEIN
1i1r	CRYSTAL STRUCTURE OF A CYTOKINE/RECEPTOR COMPLEX
1iar	INTERLEUKIN-4 / RECEPTOR ALPHA CHAIN COMPLEX
1j8k	NMR STRUCTURE OF THE FIBRONECTIN EDA DOMAIN, NMR, 20 STRUCTURES
1k85	Solution structure of the fibronectin type III domain from Bacillus circulans WL-12 Chitinase A1.
1kf9	PHAGE DISPLAY DERIVED VARIANT OF HUMAN GROWTH HORMONE COMPLEXED WITH TWO COPIES OF THE EXTRACELLULAR DOMAIN OF ITS RECEPTOR
1lwr	Solution structure of the NCAM fibronectin type III module 2
1mfn	SOLUTION NMR STRUCTURE OF LINKED CELL ATTACHMENT MODULES OF MOUSE FIBRONECTIN CONTAINING THE RGD AND SYNERGY REGIONS, 20 STRUCTURES
1n26	Crystal Structure of the extra-cellular domains of Human Interleukin-6 Receptor alpha chain
1oww	Solution structure of the first type III module of human fibronectin determined by 1H, 15N NMR spectroscopy
1p9m	Crystal structure of the hexameric human IL-6/IL-6 alpha receptor/gp130 complex
1pvh	Crystal structure of leukemia inhibitory factor in complex with gp130
1qg3	CRYSTAL STRUCTURE OF A TANDEM PAIR OF FIBRONECTIN TYPE III DOMAINS FROM THE CYTOPLASMIC TAIL OF INTEGRIN ALPHA6 BETA4
1qr4	TWO FIBRONECTIN TYPE-III DOMAIN SEGMENT FROM CHICKEN TENASCIN
1tdq	Structural basis for the interactions between tenascins and the C-type lectin domains from lecticans: evidence for a cross-linking role for tenascins
1ten	STRUCTURE OF A FIBRONECTIN TYPE III DOMAIN FROM TENASCIN PHASED BY MAD ANALYSIS OF THE SELENOMETHIONYL PROTEIN
1ttf	THE THREE-DIMENSIONAL STRUCTURE OF THE TENTH TYPE III MODULE OF FIBRONECTIN: AN INSIGHT INTO RGD-MEDIATED INTERACTIONS
1ttg	THE THREE-DIMENSIONAL STRUCTURE OF THE TENTH TYPE III MODULE OF FIBRONECTIN: AN INSIGHT INTO RGD-MEDIATED INTERACTIONS
1uc6	Solution Structure of the Carboxyl Terminal Domain of the Ciliary Neurotrophic Factor Receptor
1uem	Solution Structure of the First Fibronectin Type III domain of human KIAA1568 Protein
1uen	Solution Structure of The Third Fibronectin III Domain of Human KIAA0343 Protein
1uey	Solution Structure of The First Fibronectin Type III Domain of Human KIAA0343 protein
1ujt	Solution structure of the second fibronectin Type III domain of human KIAA1568 protein
1v5j	Solution Structure of RSGI RUH-008, fn3 domain in Human cDNA
1va9	Solution structure of the second FNIII domain of DSCAML1 protein
1wf5	Solution structure of the first Fn3 domain of Sidekick-2 protein
1wfn	The fourth FN3 domain of human sidekick-2
1wfo	The eighth FN3 domain of human sidekick-2
1wft	Solution structure of C-terminal fibronectin type III domain of mouse 1700129L13Rik protein
1wfu	Solution structure of fibronectin type III domain of mouse hypothetical protein
1wis	Solution structure of the fifth FNIII domain from human KIAA1514 protein
1wj3	Solution structure of the fourth fn3 domain of KIAA1496 protein
1wk0	Solution structure of Fibronectin type III domain derived from human KIAA0970 protein
1x3d	Solution structure of the fibronectin type-III domain of human fibronectin type-III domain containing protein 3a
1x4x	Solution structure of the 6th fibronectin type III domain from human fibronectin type III domain containing protein 3
1x4y	Solution structure of the 3rd fibronectin type III domain from mouse biregional cell adhesion molecule-related/down-regulated oncogenes (Cdon) binding protein
1x4z	Solution structure of the 2nd fibronectin type III domain from mouse biregional cell adhesion molecule-related/down-regulated oncogenes (Cdon) binding protein
1x5a	The solution structure of the second fibronectin type III domain of mouse Ephrin type-A receptor 1
1x5f	The solution structure of the first fibronectin type III domain of human Neogenin
1x5g	The solution structure of the second fibronectin type III domain of human Neogenin
1x5h	The solution structure of the third fibronectin type III domain of human Neogenin
1x5i	The solution structure of the fourth fibronectin type III domain of human Neogenin
1x5j	The solution structure of the fifth fibronectin type III domain of human Neogenin
1x5k	The solution structure of the sixth fibronectin type III domain of human Neogenin
1x5l	Solution structure of the second fn3 domain of Eph receptor A8 protein
1x5x	Solution structure of the fibronectin type-III domain of human fibronectin type III domain containing protein 3
1x5y	Solution structure of the fibronectin type-III domain of mouse myosin-binding protein C, Fast-type homolog
1x5z	Solution structure of the fibronectin type-III domain of human protein tyrosine phosphatase, receptor type, D isoform 4 variant
1zlg	Solution structure of the extracellular matrix protein anosmin-1
2aew	A model for growth hormone receptor activation based on subunit rotation within a receptor dimer
2arw	The solution structure of the membrane proximal cytokine receptor domain of the human interleukin-6 receptor
2b5i	cytokine receptor complex
2ck2	Structure of core-swapped mutant of fibronectin
2crm	Solution structure of the forth FNIII domain of human
2crz	Solution structure of the fifth FNIII domain of human fibronectin type III domain containing protein 3a
2csp	Solution structure of the FNIII domain of human RIM-binding protein 2
2cuh	Solution structure of the 31st fibronectin type III domain of the human tenascin X
2cui	Solution structure of the 31st fibronectin type III domain of the human tenascin X
2cum	The solution structure of the 33rd fibronectin type III domain of human Tenascin-X
2d9q	Crystal Structure of the Human GCSF-Receptor Signaling Complex
2db8	Solution structures of the fn3 domain of human Tripartite motif protein 9
2dbj	Solution structures of the fn3 domain of human Proto-oncogene tyrosine-protein kinase MER precursor
2djs	Solution structures of the fn3 domain of human ephrin type-B receptor 1
2dju	Solution structures of the fn3 domain of human receptor-type tyrosine-protein phosphatase F
2dkm	Solution structures of the fn3 domain of human collagen alpha-1(XX) chain
2dle	Solution structure of the fourth fn3 domain of human receptor-type tyrosine-protein phosphatase eta
2dlh	Solution structure of the second fn3 domain of human receptor-type tyrosine-protein phosphatase delta
2dm4	Solution structure of the second fn3 domain of human sorLA/LR11
2dmk	The solution structure of the FN3 domain of human Midline 2 protein
2dn7	Solution structures of the 6th fn3 domain of human receptor-type tyrosine-protein phosphatase F
2doc	Solution structure of the Fibronectin type-III domain of human Neural cell adhesion molecule 2
2e3v	Crystal structure of the first fibronectin type III domain of neural cell adhesion molecule splicing isoform from human muscle culture lambda-4.4
2e7h	Solution structure of the second fn3 domain from human Ephrin type-B receptor 4
2ed7	Solution structure of the first fibronectin type III domain of human Netrin receptor DCC
2ed8	Solution structure of the second fibronectin type III domain of human Netrin receptor DCC
2ed9	Solution structure of the third fibronectin type III domain of human Netrin receptor DCC
2edb	Solution structure of the fourth fibronectin type III domain of human Netrin receptor DCC
2edd	Solution structure of the fifth fibronectin type III domain of human Netrin receptor DCC
2ede	Solution structure of the sixth fibronectin type III domain of human Netrin receptor DCC
2edx	Solution structures of the fn3 domain of human receptor-type tyrosine-protein phosphatase F
2edy	Solution structures of the fn3 domain of human receptor-type tyrosine-protein phosphatase F
2ee2	Solution structures of the fn3 domain of human contactin 1
2ee3	Solution structures of the fn3 domain of human collagen alpha-1(XX) chain
2ekj	Solution structures of the fn3 domain of human collagen alpha-1(XX) chain
2erj	Crystal structure of the heterotrimeric interleukin-2 receptor in complex with interleukin-2
2fnb	NMR STRUCTURE OF THE FIBRONECTIN ED-B DOMAIN, NMR, 20 STRUCTURES
2gee	Crystal Structure of Human Type III Fibronectin Extradomain B and Domain 8
2gys	2.7 A structure of the extracellular domains of the human beta common receptor involved in IL-3, IL-5, and GM-CSF signalling
2h41	Solution structure of the second type III domain of human Fibronectin: minimized average structure
2h45	Solution structure of the second type III domain of human Fibronectin: ensemble of 25 structures
2ha1	Complex of the first and second type III domains of human Fibronectin in solution
2haz	Crystal structure of the first fibronectin domain of human NCAM1
2ibb	Crystal Structure of the First and Second FNIII Domains of Ihog
2ibg	Crystal Structure of Hedgehog Bound to the FNIII Domains of Ihog
2ic2	Crystal Structure of the First FNIII Domain of Ihog
2jix	Crystal structure of ABT-007 FAB fragment with the soluble domain of EPO receptor
2jll	Crystal structure of NCAM2 IgIV-FN3II
2kbg	Solution structure of the second Fibronectin type-III module of NCAM2
2lfg	Solution structure of the human prolactin receptor ecd domain d2
2m26	NMR structure of the C-terminal domain of the protein HCFC1 from Mus musculus
2mfn	SOLUTION NMR STRUCTURE OF LINKED CELL ATTACHMENT MODULES OF MOUSE FIBRONECTIN CONTAINING THE RGD AND SYNERGY REGIONS, 10 STRUCTURES
2mnu	2MNU
2n1k	2N1K
2nzi	Crystal structure of domains A168-A170 from titin
2obg	Crystal Structure of Monobody MBP-74/Maltose Binding Protein Fusion Complex
2ocf	Human estrogen receptor alpha ligand-binding domain in complex with estradiol and the E2#23 FN3 monobody
2q7n	Crystal structure of Leukemia inhibitory factor in complex with LIF receptor (domains 1-5)
2qbw	The crystal structure of PDZ-Fibronectin fusion protein
2rb8	High resolution design of a protein loop
2rbl	High resolution design of a protein loop
2uve	Structure of Yersinia enterocolitica Family 28 Exopolygalacturonase
2uvf	Structure of Yersinia enterocolitica Family 28 Exopolygalacturonase in Complex with Digalaturonic Acid
2v5y	Crystal structure of the receptor protein tyrosine phosphatase mu ectodomain
2vkw	Human NCAM, FN3 domains 1 and 2
2vkx	Human NCAM, FN3 domains 1 and 2, M610R mutant
2vtc	The structure of a glycoside hydrolase family 61 member, Cel61B from the Hypocrea jecorina.
2w1n	cohesin and fibronectin type-III double module construct from the Clostridium perfringens glycoside hydrolase GH84C
2x10	Crystal structure of the complete EphA2 ectodomain
2x11	Crystal structure of the complete EphA2 ectodomain in complex with ephrin A5 receptor binding domain
2xyc	CRYSTAL STRUCTURE OF NCAM2 IGIV-FN3I
2yrz	Solution structure of the fibronectin type III domain of human Integrin beta-4
2yuw	Solution Structure of 2nd Fibronectin Domain of Slow Type Myosin-Binding Protein C
2yux	Solution Structure of 3rd Fibronectin type three Domain of slow type Myosin-Binding Protein C
3b83	Computer-Based Redesign of a beta Sandwich Protein Suggests that Extensive Negative Design Is Not Required for De Novo beta Sheet Design.
3bpl	Crystal structure of the IL4-IL4R-Common Gamma ternary complex
3bpn	Crystal structure of the IL4-IL4R-IL13Ra ternary complex
3bpo	Crystal structure of the IL13-IL4R-IL13Ra ternary complex
3ch8	The crystal structure of PDZ-Fibronectin fusion protein
3csb	Crystal Structure of Monobody YSX1/Maltose Binding Protein Fusion Complex
3csg	Crystal Structure of Monobody YS1(MBP-74)/Maltose Binding Protein Fusion Complex
3d1m	Crystal Structure of Sonic Hedgehog Bound to the third FNIII domain of CDO
3d48	Crystal structure of a prolactin receptor antagonist bound to the extracellular domain of the prolactin receptor
3e0g	Structure of the Leukemia Inhibitory Factor Receptor (LIF-R) domains D1-D5
3ew3	the 1:2 complex between a Nterminal elongated prolactin and the extra cellular domain of the rat prolactin receptor
3f7p	Crystal structure of a complex between integrin beta4 and plectin
3f7q	First pair of Fibronectin type III domains and part of the connecting segment of the integrin beta4
3f7r	First pair of Fibronectin type III domains and part of the connecting segment of the integrin beta4
3fl7	Crystal structure of the human ephrin A2 ectodomain
3hhr	HUMAN GROWTH HORMONE AND EXTRACELLULAR DOMAIN OF ITS RECEPTOR: CRYSTAL STRUCTURE OF THE COMPLEX
3k2m	Crystal Structure of Monobody HA4/Abl1 SH2 Domain Complex
3l5h	Crystal structure of the full ectodomain of human gp130: New insights into the molecular assembly of receptor complexes
3l5i	Crystal structure of FnIII domains of human GP130 (Domains 4-6)
3l5j	Crystal structure of FnIII domains of human GP130 (Domains 4-6)
3lpw	Crystal structure of the FnIII-tandem A77-A78 from the A-band of titin
3lqm	Structure of the IL-10R2 Common Chain
3mpc	The crystal structure of a Fn3-like protein from Clostridium thermocellum
3mtr	Crystal structure of the Ig5-FN1 tandem of human NCAM
3mx0	Crystal Structure of EphA2 ectodomain in complex with ephrin-A5
3mzg	Crystal structure of a human prolactin receptor antagonist in complex with the extracellular domain of the human prolactin receptor
3n06	A mutant human Prolactin receptor antagonist H27A in complex with the extracellular domain of the human prolactin receptor
3n0p	A mutant human Prolactin receptor antagonist H30A in complex with the extracellular domain of the human prolactin receptor
3n1f	Crystal Structure of IhhN bound to CDOFn3
3n1g	Crystal structure of DhhN bound to BOCFn3
3n1m	Crystal Structure of IhhN bound to BOCFn3
3n1p	Crystal Structure of IhhN bound to BOCFn3
3n1q	Crystal Structure of DhhN bound to CDOFn3
3ncb	A mutant human Prolactin receptor antagonist H180A in complex with the extracellular domain of the human prolactin receptor
3ncc	A human Prolactin receptor antagonist in complex with the mutant extracellular domain H188A of the human prolactin receptor
3nce	A mutant human Prolactin receptor antagonist H27A in complex with the mutant extracellular domain H188A of the human prolactin receptor
3ncf	A mutant human Prolactin receptor antagonist H30A in complex with the mutant extracellular domain H188A of the human prolactin receptor
3npz	Prolactin Receptor (PRLR) Complexed with the Natural Hormone (PRL)
3p4l	Crystal structure of a hemojuvelin-binding fragment of neogenin
3qaz	IL-2 mutant D10 ternary complex
3qb7	Interleukin-4 mutant RGA bound to cytokine receptor common gamma
3qht	Crystal Structure of the Monobody ySMB-1 bound to yeast SUMO
3qwq	Crystal structure of the extracellular domain of the epidermal growth factor receptor in complex with an adnectin
3qwr	Crystal structure of IL-23 in complex with an adnectin
3r4d	Crystal structure of mouse coronavirus receptor-binding domain complexed with its murine receptor
3r8q	Structure of Fibronectin domain 12-14
3rzw	Crystal Structure of the Monobody ySMB-9 bound to human SUMO1
3s98	human IFNAR1
3se3	human IFNa2-IFNAR ternary complex
3se4	human IFNw-IFNAR ternary complex
3t04	Crystal structure of monobody 7c12/abl1 sh2 domain complex
3t1w	Structure of the four-domain fragment Fn7B89 of oncofetal fibronectin
3tes	Crystal Structure of Tencon
3teu	Crystal structure of fibcon
3tgx	IL-21:IL21R complex
3uto	Twitchin kinase region from C.elegans (Fn31-NL-kin-CRD-Ig26)
3uyo	Crystal structure of monobody SH13/ABL1 SH2 domain complex
3wcy	Murine Ifnar1 in complex with interferon-beta
3wih	3WIH
4bk4	crystal structure of the human EphA4 ectodomain
4bk5	crystal structure of the human EphA4 ectodomain in complex with human ephrin A5 (amine-methylated sample)
4bka	crystal structure of the human EphA4 ectodomain in complex with human ephrin A5
4bkf	crystal structure of the human EphA4 ectodomain in complex with human ephrinB3
4bq6	Crystal structure of the RGMB-NEO1 complex form 1
4bq7	Crystal structure of the RGMB-Neo1 complex form 2
4bq8	Crystal structure of the RGMB-NEO1 complex form 3
4bq9	Crystal structure of the FN5 and FN6 domains of NEO1, form 1
4bqb	Crystal structure of the FN5 and FN6 domains of NEO1, form 2
4bqc	Crystal structure of the FN5 and FN6 domains of NEO1 bound to SOS
4doh	IL20/IL201/IL20R2 Ternary Complex
4gh7	Crystal structure of Anticalin N7A in complex with oncofetal fibronectin fragment Fn7B8
4go6	Crystal structure of HCF-1 self-association sequence 1
4gs7	Structure of the Interleukin-15 quaternary complex
4hlj	Axon Guidance Receptor
4huk	MATE transporter NorM-NG in complex with TPP and monobody
4hul	MATE transporter NorM-NG in complex with Cs+ and monobody
4hum	MATE transporter NorM-NG in complex with ethidium and monobody
4hun	MATE transporter NorM-NG in complex with R6G and monobody
4hwb	Crystal structure of ectodomain 3 of the IL-13 receptor alpha 1 in complex with a human neutralizing monoclonal antibody fragment
4i18	Crystal structure of human prolactin receptor complexed with Fab fragment
4je4	Crystal Structure of Monobody NSa1/SHP2 N-SH2 Domain Complex
4jeg	Crystal Structure of Monobody CS1/SHP2 C-SH2 Domain Complex
4jmg	Crystal structure of the synthetic protein in complex with pY peptide
4jmh	Crystal structure of synthetic protein in complex with double pY peptide
4k0v	Structural basis for angiopoietin-1 mediated signaling initiation
4lpt	Crystal structure of monomeric TENCON variant P54CR4-31
4lpu	Crystal structure of TENCON variant P40AR2-32R2
4lpv	Crystal structure of TENCON variant P41BR3-42
4lpw	Crystal structure of TENCON variant A6
4lpx	Crystal structure of TENCON variant D4
4lpy	Crystal structure of TENCON variant G10
4lsd	Myokine structure
4lxo	4LXO
4m4p	Crystal structure of EPHA4 ectodomain
4m4r	Epha4 ectodomain complex with ephrin a5
4m6a	N-Terminal beta-Strand Swapping in a Consensus Derived Alternative Scaffold Driven by Stabilizing Hydrophobic Interactions
4mmx	Integrin AlphaVBeta3 ectodomain bound to the tenth domain of Fibronectin
4mmy	Integrin AlphaVBeta3 ectodomain bound to the tenth domain of Fibronectin with the IAKGDWND motif
4mmz	Integrin AlphaVBeta3 ectodomain bound to an antagonistic tenth domain of Fibronectin
4n5u	Crystal structure of the 4th FN3 domain of human Protein Tyrosine phosphatase, receptor type F [PSI-NYSGRC-006240]
4n68	Crystal structure of an internal FN3 domain from human Contactin-5 [PSI-NYSGRC-005804]
4nkq	4NKQ
4nn5	Cytokine receptor complex - Crystal form 1A
4nn6	Cytokine receptor complex - Crystal form 1B
4nn7	Cytokine receptor complex - Crystal form 2
4nzd	4NZD
4o00	4O00
4ov6	4OV6
4pbx	4PBX
4pln	4PLN
4plo	4PLO
4q58	4Q58
4q66	4Q66
4qqv	4QQV
4rs1	4RS1
4s0s	4S0S
4s0t	4S0T
4s3l	4S3L
4u3h	4U3H
4ui2	4UI2
4urt	4URT
4wtw	4WTW
4wtx	4WTX
4y5v	4Y5V
4y5x	4Y5X
4y5y	4Y5Y
4y61	4Y61
4yfd	4YFD
4yfe	4YFE
4yfg	4YFG
4yg8	4YG8
4yh7	4YH7
4zxb	4ZXB
5a40	5A40
5a43	5A43
5c6p	5C6P
5dc0	5DC0
5dc4	5DC4
5dc9	5DC9
5dft	5DFT
5dwu	5DWU
5e4e	5E4E
5e4q	5E4Q
5e4s	5E4S
5e52	5E52
5e53	5E53
5e55	5E55
5e7l	5E7L
5e95	5E95
5ecj	5ECJ
5eh1	5EH1
5fm4	5FM4
5fm5	5FM5
5fm8	5FM8
5fmv	5FMV
5fn6	5FN6
5fn8	5FN8
5fxb	5FXB
5g56	5G56
5hx2	5HX2
5i99	5I99
5iv5	5IV5
5iv7	5IV7
5j67	5J67
5j68	5J68
5j7c	5J7C
5j7k	5J7K
5kbn	5KBN
5kf4	5KF4
5kom	5KOM
5kvm	5KVM
5l2h	5L2H
5lkn	5LKN

Links (links to other resources describing this domain)

• PROSITE: FN3_DOMAIN
• INTERPRO: IPR003961
• PFAM: fn3