Combined Automated Annotation using Multiple IEA Methods

UniProtKB:A0A0H2M8Q2

UniProtKB entry A0A0H2M8Q2 (A0A0H2M8Q2_VARPD): Coenzyme PQQ synthesis protein B

A0A0H2M8Q2 (VPARA_00950, pqqB1/pqqB) is a 307-residue member of the PqqB family (HAMAP MF_00653, InterPro IPR011842, NCBIfam TIGR02108, PANTHER PTHR42663:SF7) containing a metallo-beta-lactamase domain (residues 53-274, Pfam PF12706) in the pyrroloquinoline quinone biosynthesis pathway.

"CC -!- PATHWAY: Cofactor biosynthesis; pyrroloquinoline quinone biosynthesis. CC {ECO:0000256|ARBA:ARBA00004886, ECO:0000256|HAMAP-Rule:MF_00653}."
Contains a metallo-beta-lactamase fold domain spanning residues 53 to 274 (Pfam PF12706).

"FT DOMAIN 53..274 FT /note="Metallo-beta-lactamase" FT /evidence="ECO:0000259|Pfam:PF12706""

Discovery of Hydroxylase Activity for PqqB Provides a Missing Link in the Pyrroloquinoline Quinone Biosynthetic Pathway.

Biochemical, mass-spectrometric, 18O2-labeling, and X-ray crystallographic studies demonstrate that bacterial PqqB is an Fe(2+)-dependent non-heme hydroxylase within the metallo-beta-lactamase superfamily that catalyzes oxygen-insertion reactions on PqqA-derived cross-linked intermediates to form the quinone moiety of PQQ.

"Here we show evidence that the remaining essential biosynthetic enzyme PqqB is an iron-dependent hydroxylase catalyzing oxygen-insertion reactions that are proposed to produce the quinone moiety of the mature PQQ cofactor."
Metal-binding and kinetic studies identify Fe(2+) coordinated by a 2-His/1-Asp ligand set as the catalytic metal cofactor of PqqB, alongside a tightly bound structural Zn(2+) site.

"The collective observations in this work strongly implicate PqqB as a novel non-heme hydroxylase."

PMID:32731194

Biogenesis of the peptide-derived redox cofactor pyrroloquinoline quinone.

Confirms that PqqB is an iron-dependent hydroxylase that oxidizes the tyrosine ring of the PqqA-derived Glu-Tyr cross-linked intermediate to a hydroxyquinone derivative that cyclizes to AHQQ, the direct substrate of PqqC.

"Detailed kinetic analyses have confirmed that PqqB is a previously unknown iron-dependent hydroxylase, indicating a cross-over between the MBL superfamily and the non-heme iron hydroxylases."