Taxonomic distribution of proteins containing IL6 domains

The IL6 domain within your query sequence starts at position 55 and ends at position 209, and its E-value is 2.1e-98.

1.9 A crystal structure of interleukin 6: implications for a novel mode of receptor dimerization and signaling.

Somers W, Stahl M, Seehra JS
EMBO J. 1997; 16: 989-97

Interleukin 6 (IL-6) has many biological activities in vivo, and deregulation has been implicated in many disease processes. IL-6, a 185 amino acid polypeptide was refolded, purified and crystallized. The crystals diffracted to beyond 1.9 A and the structure was solved using single isomorphous replacement. The X-ray structure of IL-6 is composed of a four helix bundle linked by loops and an additional mini-helix. 157 out of 185 residues are well defined in the final structure, with 18 N-terminal and 8 A-B loop amino acids displaying no interpretable electron density. The three-dimensional structure has been used to construct a model of IL-6 interacting with the IL-6 receptor (alpha-chain) and gp130 (beta-chain) that gives new insight into the process of molecular recognition and signaling. Based on this model, we predict a fourth binding site on IL-6, a low affinity IL-6-IL-6 interaction, which may be necessary for the sequential assembly of a functional hexameric IL-6 receptor complex.

Is IL-6 both a cytokine and a neurotrophic factor?

Wagner JA
J Exp Med. 1996; 183: 2417-9

Interleukin-6-type cytokines in myeloproliferative disease.

Hawley RG
Ann N Y Acad Sci. 1995; 762: 294-307

Interleukin-6: a comprehensive review.

Lotz M
Cancer Treat Res. 1995; 80: 209-33

Interleukin-6 in biology and medicine.

Akira S, Taga T, Kishimoto T
Adv Immunol. 1993; 54: 1-78

Crystal structure of canine and bovine granulocyte-colony stimulating factor (G-CSF).

Lovejoy B, Cascio D, Eisenberg D
J Mol Biol. 1993; 234: 640-53

The crystal structures of recombinant canine and bovine granulocyte colony stimulating factor (G-CSF) have been determined by X-ray crystallography, using molecular replacement with recombinant human G-CSF as a model. G-CSF is a member of the cytokine family of glycoproteins that stimulate the differentiation and proliferation of blood cells. Human, bovine and canine G-CSF all have a molecular mass of about 19 kDa and share an amino acid sequence identity of about 80%. Two crystal forms of canine G-CSF have been solved. Form I recombinant canine G-CSF (rcG-CSFI; space group C2) contains one molecule in the asymmetric unit while form II canine G-CSF (rcG-CSFII; space group P2(1)) has two molecules in the asymmetric unit and bovine G-CSF (rbG-CSF; space group P2(1)2(1)2(1)) contains one molecule in the asymmetric unit. rcG-CSFI has been refined to an R factor of 20.7% with data to 2.3 A resolution and rcG-CSFII has been refined to an R factor of 19.3% with data to 2.2 A resolution. rbG-CSF has been refined to an R factor of 21.3% with data to 1.7 A resolution. The structure of human, canine and bovine G-CSF is an antiparallel 4-alpha-helical bundle with up-up-down-down connectivity. With the exception of one highly exposed loop (residues 66 to 74), the human, canine and bovine structures are very similar to each other. Using our series of G-CSF crystal structures we developed a function that describes the probability that a particular residue position (i) contributes to a G-CSF receptor binding site based on two principles, (1) high sequence conservation in the primary sequence of human, bovine, canine and murine G-CSF and (2) conservation of high solvent accessibility in the human, bovine and canine crystal structures. On the basis of this probability function as well as a comparison of G-CSF to the crystal structure of human growth hormone (hGH) complexed with the extracellular domain of the human growth hormone receptor (hGHbp), residues that contribute to potential G-CSF receptor binding sites are identified.