Mechanism of assembly of the Bis(Molybdopterin guanine dinucleotide)molybdenum cofactor in Rhodobacter sphaeroides dimethyl sulfoxide reductase.

Published

Journal Article

A fully defined in vitro system has been developed for studying the mechanism of assembly of the bis(molybdopterin guanine dinucleotide)molybdenum cofactor in Rhodobacter sphaeroides dimethyl sulfoxide reductase (DMSOR). R. sphaeroides DMSOR expressed in a mobA(-) Escherichia coli strain lacks molybdopterin and molybdenum but contains a full complement of guanine in the form of GMP and GDP. Escherichia coli MobA, molybdopterin-Mo, GTP, and MgCl(2) are required and sufficient for the in vitro activation of purified DMSOR expressed in the absence of MobA. High levels of MobA inhibit the in vitro activation. A chaperone is not required for the in vitro activation process. The reconstituted DMSOR can exhibit up to 73% of the activity observed in recombinant DMSOR purified from a wild-type strain. The use of radiolabeled GTP has demonstrated incorporation of the guanine moiety from the GTP into the activated DMSOR. No role was observed for E. coli MobB in the in vitro activation of apo-DMSOR. This work also represents the first time that the MobA-mediated conversion of molybdopterin to molybdopterin guanine dinucleotide has been demonstrated directly without using the activation of a molybdoenzyme as an indicator for cofactor formation.

Full Text

Duke Authors

Cited Authors

  • Temple, CA; Rajagopalan, KV

Published Date

  • December 22, 2000

Published In

Volume / Issue

  • 275 / 51

Start / End Page

  • 40202 - 40210

PubMed ID

  • 10978348

Pubmed Central ID

  • 10978348

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.M007407200

Language

  • eng

Conference Location

  • United States