The domain within your query sequence starts at position 141 and ends at position 173; the E-value for the PQQ domain shown below is 2.61e2.

PCVSAAEQEIFFGSHDCFIYCCSKEGHLRWKFE

PQQ

beta-propeller repeat

• SMART accession number: SM00564
• Description: Beta-propeller repeat occurring in enzymes with pyrrolo-quinoline quinone (PQQ) as cofactor, in Ire1p-like Ser/Thr kinases, and in prokaryotic dehydrogenases.
• Interpro abstract (IPR018391):

  Pyrrolo-quinoline quinone (PQQ) is a redox coenzyme, which serves as a cofactor for a number of enzymes (quinoproteins) and particularly for some bacterial dehydrogenases [ (PUBMED:2549854) (PUBMED:2572081) (PUBMED:18838797) ]. A number of bacterial quinoproteins belong to this family.

  Enzymes in this group have repeats of a beta propeller.

There are 237300 PQQ domains in 48510 proteins in SMART's nrdb database.

Literature (relevant references for this domain)

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

• Xia Z, Dai W, Zhang Y, White SA, Boyd GD, Mathews FS
• Determination of the gene sequence and the three-dimensional structure at 2.4 angstroms resolution of methanol dehydrogenase from Methylophilus W3A1.
• J Mol Biol. 1996; 259: 480-501

The DNA sequences for the genes encoding the heavy and light subunits of methanol dehydrogenase from Methylophilus methylotrophus W3A1 have been determined. The deduced amino acid sequence has enabled the structure of the enzyme to be refined at 2.4 angstrom resolution against X-ray data collected on a Hamlin area detector. The structure was refined using the programs PROFFT and X-PLOR with several model building step interspersed. The final model contains two heavy chains (571 amino acids), two light chains (69 amino acids), two molecules of pyrroloquinoline quinone, two Ca2+ and 521 solvent molecules. Each half molecule contains four disulfide linkages and four cis peptides. One of the disulfides is formed from two adjacent cysteine residues linked by a trans peptide which creates a novel eight-membered ring. The heavy subunit is an 8-fold beta-propeller, each "blade" of which is a four-stranded antiparallel twisted beta-sheet. The light chain is an elongated subunit stretching across the surface of the heavy subunit, with residues 1 to 32 containing four beta-turns and residues 33 to 62 forming a helix; however, it neither interacts with the active site, nor the other HL dimer and its functional role is obscure. Around the 8-fold beta-propeller there is a repeating pattern of tryptophan residues located in the outer strand of seven of the eight beta-leaflets, each packed between adjacent leaflets. Each of these tryptophan residues is centered in the beta-strand and participates in the main chain hydrogen bonding of the sheet. Five of the seven tryptophan residues have closely similar interactions with the adjacent beta-leaflet including stacking of the tryptophan indole rings against a peptide plane and formation of a hydrogen bond from NE1 of the indole ring to a main-chain carbonyl. This repeating pattern is conserved over a number of MEDH sequences. The PQQ is located on the pseudo 8-fold rotation axis of the heavy subunit, in a funnel-shaped internal cavity, sandwiched between the indole ring of Trp237 and the two sulfur atoms of the Cys103-Cys104 vicinal disulfide. A hexacoordinate Ca2+ is bound in the active site by one nitrogen and five oxygen ligands, three from the PQQ and the others from two protein side-chains. In the active site an isolated solvent molecule is bound to the O5 of PQQ and to a nearby aspartate side-chain; its position may be the binding site for methanol. The aspartate might than serve as a general base for proton abstraction from the substrate hydroxyl. The C5 atom of PQQ could be activated by electrophilic catalysis by a nearby argenine side-chain or by the calcium ion bound to PQQ.

• Blake CC, Ghosh M, Harlos K, Avezoux A, Anthony C
• The active site of methanol dehydrogenase contains a disulphide bridge between adjacent cysteine residues.
• Nat Struct Biol. 1994; 1: 102-5

Adjacent cysteine residues can only form disulphide bridges in a distorted structure containing a cis-peptide link. Such bridges are extremely uncommon, identified so far in the acetyl choline receptor alone where the structure of the bridge is undetermined. Here we present the first molecular description of a disulphide bridge of this type in the quinoprotein methanol dehydrogenase from Methylobacterium extorquens. We show that this structure occurs in close proximity to the pyrrolo-quinoline quinone prosthetic group and a calcium ion in the active site of the enzyme. This unusual disulphide bridge appears to play a role in the electron transfer reaction mediated by methanol dehydrogenase.

• Duine JA, Jongejan JA
• Quinoproteins, enzymes with pyrrolo-quinoline quinone as cofactor.
• Annu Rev Biochem. 1989; 58: 403-26

Metabolism (metabolic pathways involving proteins which contain this domain)

% proteins involved	KEGG pathway ID	Description
19.73	map00030	Pentose phosphate pathway
13.87	map00680	Methane metabolism
13.87	map00010	Glycolysis / Gluconeogenesis
13.87	map00631	1,2-Dichloroethane degradation
13.87	map00650	Butanoate metabolism
13.87	map00640	Propanoate metabolism
2.13	map00440	Aminophosphonate metabolism
2.13	map00903	Limonene and pinene degradation
2.13	map00362	Benzoate degradation via hydroxylation
1.07	map00562	Inositol phosphate metabolism
1.07	map00632	Benzoate degradation via CoA ligation
1.07	map00400	Phenylalanine, tyrosine and tryptophan biosynthesis
0.53	map03090	Type II secretion system
0.27	map00300	Lysine biosynthesis
0.27	map00860	Porphyrin and chlorophyll metabolism
0.27	map00310	Lysine degradation

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 PQQ domain which could be assigned to a KEGG orthologous group, and not all proteins containing PQQ 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 PQQ domains in PDB

PDB code	Title
1flg	CRYSTAL STRUCTURE OF THE QUINOPROTEIN ETHANOL DEHYDROGENASE FROM PSEUDOMONAS AERUGINOSA
1g72	CATALYTIC MECHANISM OF QUINOPROTEIN METHANOL DEHYDROGENASE: A THEORETICAL AND X-RAY CRYSTALLOGRAPHIC INVESTIGATION
1h4i	Methylobacterium extorquens methanol dehydrogenase
1h4j	Methylobacterium extorquens methanol dehydrogenase D303E mutant
1kb0	Crystal Structure of Quinohemoprotein Alcohol Dehydrogenase from Comamonas testosteroni
1kv9	Structure at 1.9 A Resolution of a Quinohemoprotein Alcohol Dehydrogenase from Pseudomonas putida HK5
1lrw	Crystal structure of methanol dehydrogenase from P. denitrificans
1w6s	The high resolution structure of methanol dehydrogenase from methylobacterium extorquens
1yiq	Molecular cloning and structural analysis of quinohemoprotein alcohol dehydrogenase ADHIIG from Pseudomonas putida HK5. Compariison to the other quinohemoprotein alcohol dehydrogenase ADHIIB found in the same microorganism.
2ad6	crystal structure of methanol dehydrogenase from M. W3A1 (form C)
2ad7	crystal structure of methanol dehydrogenase from M. W3A1 (form C) in the presence of methanol
2ad8	crystal structure of methanol dehydrogenase from M. W3A1 (form C) in the presence of ethanol
2be1	Structure of the compact lumenal domain of yeast Ire1
2d0v	Crystal structure of methanol dehydrogenase from Hyphomicrobium denitrificans
2hz6	The crystal structure of human IRE1-alpha luminal domain
2yh3	The structure of BamB from E. coli
2yms	Structure and assembly of a b-propeller with nine blades and a new conserved repetitive sequence motif
3hxj	Crystal Structure of Pyrrolo-quinoline quinone (PQQ_DH) from Methanococcus maripaludis, Northeast Structural Genomics Consortium Target MrR86
3p1l	Crystal structure of Escherichia coli BamB, a lipoprotein component of the beta-barrel assembly machinery complex, native crystals.
3prw	Crystal structure of the lipoprotein BamB
3q54	Crystal structure of Escherichia coli BamB
3q7m	The crystal structure of BamB from the BAM complex in spacegroup I222
3q7n	The crystal structure of BamB from the BAM complex in spacegroup P212121
3q7o	The crystal structure of BamB from the BAM complex in spacegroup P213
4aah	METHANOL DEHYDROGENASE FROM METHYLOPHILUS W3A1
4cvb	4CVB
4cvc	4CVC
4hdj	Crystal Structure of BamB from Pseudomonas aeruginosa
4imm	The crystal structure of BamB from Moraxella catarrhalis
4mae	Methanol dehydrogenase from Methylacidiphilum fumariolicum SolV
4mh1	4MH1
4pk1	4PK1
4tqo	4TQO
4xga	4XGA
5ayw	5AYW
5d0o	5D0O
5ljo	5LJO

Links (links to other resources describing this domain)

• INTERPRO: IPR018391