GONUTS has been updated to MW1.31 Most things seem to be working but be sure to report problems.

Have any questions? Please email us at ecoliwiki@gmail.com

PMID:8910376

From GONUTS
Jump to: navigation, search
Citation

Heath, RJ and Rock, CO (1996) Roles of the FabA and FabZ beta-hydroxyacyl-acyl carrier protein dehydratases in Escherichia coli fatty acid biosynthesis. J. Biol. Chem. 271:27795-801

Abstract

There are two genes, fabA and fabZ, encoding beta-hydroxyacyl-acyl carrier protein (ACP) dehydratases that function in the dissociated, type II fatty acid synthase system of Escherichia coli. We have investigated their roles in fatty acid synthesis by purifying the two proteins and reconstituting cycles of fatty acid synthesis in vitro using five other purified proteins. FabA and FabZ exhibited broad, overlapping chain length specificities. The FabZ dehydratase efficiently catalyzed the dehydration of short chain beta-hydroxyacyl-ACPs and long chain saturated and unsaturated beta-hydroxyacyl-ACPs. FabA was most active on intermediate chain length beta-hydroxyacyl-ACPs and also possessed significant activity toward both short and long chain saturated beta-hydroxyacyl-ACPs. Significantly, FabA was virtually inactive in the dehydration of long chain unsaturated beta-hydroxyacyl-ACP. The introduction of the double bond at the 10-carbon stage of fatty acid synthesis by FabA was only detected in the presence of beta-ketoacyl-ACP synthase I (FabB). A yeast two-hybrid analysis failed to detect an interaction between FabA and FabB, therefore the channeling of intermediates toward unsaturated fatty acid synthesis by FabB was attributed to the affinity of the condensing enzyme for cis-decenoyl-ACP. The broad substrate specificity of FabZ coupled with the inactivity of FabA toward a long chain unsaturated beta-hydroxyacyl-ACP provides a biochemical explanation for the phenotypes of cells with genetically altered levels of the two dehydratases.

Links

PubMed

Keywords

Cloning, Molecular; Escherichia coli/enzymology; Fatty Acid Synthetase Complex, Type II; Fatty Acids/biosynthesis; Fatty Acids, Unsaturated/metabolism; Hydro-Lyases/metabolism; Kinetics; Models, Biological; Recombinant Proteins/metabolism; Saccharomyces cerevisiae; Substrate Specificity

Significance

Annotations

Gene product Qualifier GO Term Evidence Code with/from Aspect Extension Notes Status

ECOLI:FABZ

acts_upstream_of_or_within

GO:0006633: fatty acid biosynthetic process

ECO:0000314: direct assay evidence used in manual assertion

P

Seeded From UniProt

complete

ECOLI:FABA

enables

GO:0047451: 3-hydroxyoctanoyl-[acyl-carrier-protein] dehydratase activity

ECO:0000314: direct assay evidence used in manual assertion

F

Seeded From UniProt

complete

ECOLI:FABA

enables

GO:0008693: 3-hydroxydecanoyl-[acyl-carrier-protein] dehydratase activity

ECO:0000314: direct assay evidence used in manual assertion

F

Seeded From UniProt

complete

ECOLI:FABZ

enables

GO:0008693: 3-hydroxydecanoyl-[acyl-carrier-protein] dehydratase activity

ECO:0000314: direct assay evidence used in manual assertion

F

Seeded From UniProt

complete

ECOLI:FABZ

involved_in

GO:0006633: fatty acid biosynthetic process

ECO:0000314: direct assay evidence used in manual assertion

P

Seeded From UniProt

complete

ECOLI:FABZ

enables

GO:0047451: 3-hydroxyoctanoyl-[acyl-carrier-protein] dehydratase activity

ECO:0000314: direct assay evidence used in manual assertion

F

Seeded From UniProt

complete


See also

References

See Help:References for how to manage references in GONUTS.