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- **************************************************************
- * Alpha-isopropylmalate and homocitrate synthases signatures *
- **************************************************************
-
- The following enzymes have been shown [1] to be functionally as well as
- evolutionary related:
-
- - Alpha-isopropylmalate synthase (EC 4.1.3.12) which catalyzes the first step
- in the biosynthesis of leucine, the condensation of acetyl-CoA and alpha-
- ketoisovalerate to form 2-isopropylmalate synthase.
- - Homocitrate synthase (EC 4.1.3.21) (gene nifV) which is involved in the
- biosynthesis of the iron-molybdenum cofactor of nitrogenase and catalyzes
- the condensation of acetyl-CoA and alpha-ketoglutarate into homocitrate.
-
- We have selected two conserved regions as signature patterns for these
- enzymes. The first region is located in the N-terminal section while the
- second region is located in the central section and contains two conserved
- histidine residues which could be implicated in the catalytic mechanism.
-
- -Consensus pattern: T-x-L-R-D-G-x-Q-x(10)-K
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Consensus pattern: [LIVMF]-x(2)-H-x-H-[DN]-D-x-G-x-[GAS]-x-[GAS]
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Last update: October 1993 / First entry.
-
- [ 1] Wang S.-Z., Dean D.R., Chen J.-S., Johnson J.L.
- J. Bacteriol. 173:3041-3046(1991).
-