malonyl CoA reductase (malonate semialdehyde-forming);
NADP-dependent malonyl CoA reductase;
malonyl CoA reductase (NADP)

Oxidoreductases;
Acting on the aldehyde or oxo group of donors;
With NAD+ or NADP+ as acceptor

malonate semialdehyde:NADP+ oxidoreductase (malonate semialdehyde-forming)

malonate semialdehyde + CoA + NADP+ = malonyl-CoA + NADPH + H+ [RN:R00740]

R00740

malonate semialdehyde [CPD:C00222];
CoA [CPD:C00010];
NADP+ [CPD:C00006]

Requires Mg2+. Catalyses the reduction of malonyl-CoA to malonate semialdehyde, a key step in the 3-hydroxypropionate and the 3-hydroxypropionate/4-hydroxybutyrate cycles, autotrophic CO2 fixation pathways found in some green non-sulfur phototrophic bacteria and some thermoacidophilic archaea, respectively [1,2]. The enzyme from Sulfolobus tokodaii has been purified, and found to contain one RNA molecule per two subunits [3]. The enzyme from Chloroflexus aurantiacus is bifunctional, and also catalyses the next reaction in the pathway, EC 1.1.1.298 [3-hydroxypropionate dehydrogenase (NADP+)] [4].

1  [PMID:8354269]

Strauss G, Fuchs G

Enzymes of a novel autotrophic CO2 fixation pathway in the phototrophic bacterium Chloroflexus aurantiacus, the 3-hydroxypropionate cycle.

Eur. J. Biochem. 215 (1993) 633-43.

2  [PMID:18079405]

Berg IA, Kockelkorn D, Buckel W, Fuchs G

A 3-hydroxypropionate/4-hydroxybutyrate autotrophic carbon dioxide assimilation pathway in Archaea.

Science. 318 (2007) 1782-6.

3  [PMID:17041055]

Alber B, Olinger M, Rieder A, Kockelkorn D, Jobst B, Hugler M, Fuchs G

Malonyl-coenzyme A reductase in the modified 3-hydroxypropionate cycle for autotrophic carbon fixation in archaeal Metallosphaera and Sulfolobus spp.

J. Bacteriol. 188 (2006) 8551-9.

4  [PMID:11948153]

Hugler M, Menendez C, Schagger H, Fuchs G

Malonyl-coenzyme A reductase from Chloroflexus aurantiacus, a key enzyme of the 3-hydroxypropionate cycle for autotrophic CO(2) fixation.

J. Bacteriol. 184 (2002) 2404-10.