HMM Summary Page: TIGR03150

Functionbeta-ketoacyl-acyl-carrier-protein synthase II
Gene SymbolfabF
Trusted Cutoff493.75
Domain Trusted Cutoff493.75
Noise Cutoff437.40
Domain Noise Cutoff437.40
Isology Typeequivalog
EC Number2.3.1.179
HMM Length407
Mainrole CategoryFatty acid and phospholipid metabolism
Subrole CategoryBiosynthesis
Gene Ontology TermGO:0006633: fatty acid biosynthetic process biological_process
GO:0033817: beta-ketoacyl-acyl-carrier-protein synthase II activity molecular_function
AuthorSelengut J
Entry DateNov 9 2006 4:12PM
Last ModifiedFeb 14 2011 3:27PM
Comment3-oxoacyl-[acyl-carrier-protein] synthase 2 (KAS-II, FabF) is involved in the condensation step of fatty acid biosynthesis in which the malonyl donor group is decarboxylated and the resulting carbanion used to attack and extend the acyl group attached to the acyl carrier protein [1]. Most genomes encoding fatty acid biosynthesis contain a number of condensing enzymes, often of all three types: 1, 2 and 3. Synthase 2 is mechanistically related to synthase 1 (KAS-I, FabB) containing a number of absolutely conserved catalytic residues in common [2]. This model is based primarily on genes which are found in apparent operons with other essential genes of fatty acid biosynthesis (GenProp0681). The large gap between the trusted cutoff and the noise cutoff contains many genes which are not found adjacent to genes of the fatty acid pathway in genomes that often also contain a better hit to this model. These genes may be involved in other processes such as polyketide biosyntheses. Some genomes contain more than one above-trusted hit to this model which may result from recent paralogous expansions. Second hits to this model which are not next to other fatty acid biosynthesis genes may be involved in other processes. FabB sequences should fall well below the noise cutoff of this model.
ReferencesRN [1] RM PMID: 11152607 RT The crystal structure of beta-ketoacyl-acyl carrier protein synthase II from Synechocystis sp. at 1.54 A resolution and its relationship to other condensing enzymes. RA Moche M, Dehesh K, Edwards P, Lindqvist Y RL J Mol Biol. 2001 Jan 19;305(3):491-503. RN [2] RM PMID: 16441657 RT Fatty acid synthesis. Role of active site histidines and lysine in Cys-His-His-type beta-ketoacyl-acyl carrier protein synthases. RA von Wettstein-Knowles P, Olsen JG, McGuire KA, Henriksen A RL FEBS J. 2006 Feb;273(4):695-710.
Genome PropertyGenProp0681: fatty acid biosynthesis from acetyl-CoA (HMM)