1h4i

From Proteopedia

Revision as of 14:23, 5 November 2007

METHYLOBACTERIUM EXTORQUENS METHANOL DEHYDROGENASE

Overview

BACKGROUND: Methanol dehydrogenase (MDH) is a bacterial periplasmic, quinoprotein; it has pyrrolo-quinoline quinone (PQQ) as its prosthetic, group, requires Ca2+ for activity and uses cytochrome cL as its electron, acceptor. Low-resolution structures of MDH have already been determined., RESULTS: The structure of the alpha 2 beta 2 tetramer of MDH from, Methylobacterium extorquens has now been determined at 1.94 A with an, R-factor of 19.85%. CONCLUSIONS: The alpha-subunit of MDH has an, eight-fold radial symmetry, with its eight beta-sheets stabilized by a, novel tryptophan docking motif. The PQQ in the active site is held in, place by a coplanar tryptophan and by a novel disulphide ring formed, between adjacent cysteines which are bonded by an unusual non-planar trans, peptide bond. One of the carbonyl oxygens of PQQ is bonded to the Ca2+, probably facilitating attack on the substrate, and the other carbonyl, oxygen is out of the plane of the ring, confirming the presence of the, predicted free-radical semiquinone form of the prosthetic group.

About this Structure

1H4I is a Protein complex structure of sequences from Methylobacterium extorquens with CA and PQQ as ligands. Active as Alcohol dehydrogenase (acceptor), with EC number 1.1.99.8 Structure known Active Sites: AC1, AC2, AC3 and AC4. Full crystallographic information is available from OCA.

Reference

The refined structure of the quinoprotein methanol dehydrogenase from Methylobacterium extorquens at 1.94 A., Ghosh M, Anthony C, Harlos K, Goodwin MG, Blake C, Structure. 1995 Feb 15;3(2):177-87. PMID:7735834

Page seeded by OCA on Mon Nov 5 16:28:33 2007