3-Hydroxypropionyl-coenzyme A synthetase from Metallosphaera sedula, an enzyme involved in autotrophic CO2 fixation.

ABSTRACT: A modified 3-hydroxypropionate cycle has been proposed as the autotrophic CO2 fixation pathway for the thermoacidophilic crenarchaeon Metallosphaera sedula. The cycle requires the reductive conversion of 3-hydroxypropionate to propionyl-coenzyme A (propionyl-CoA). The specific activity of the 3-hydroxypropionate-, CoA-, and MgATP-dependent oxidation of NADPH in autotrophically grown cells was 0.023 micromol min(-1) mg protein(-1). The reaction sequence is catalyzed by at least two enzymes. The first enzyme, 3-hydroxypropionyl-CoA synthetase, catalyzes the following reaction: 3-hydroxypropionate + ATP + CoA --> 3-hydroxypropionyl-CoA + AMP + PP(i). The enzyme was purified 95-fold to a specific activity of 18 micromol min(-1) mg protein(-1) from autotrophically grown M. sedula cells. An inte

SUBMITTER: Alber BE 

PROVIDER: S-EPMC2238213 | biostudies-literature | 2008 Feb

REPOSITORIES: biostudies-literature