Modifying the determinants of alpha-ketoacid substrate selectivity in mycobacterium tuberculosis alpha-isopropylmalate synthase

作者：Hunter Michael F C; Parker Emily J^*

来源：FEBS LETTERS, 2014, 588(9): 1603-1607.

DOI：10.1016/j.febslet.2014.02.053

• Leucine biosynthesis
• Citramalate synthase
• Homocitrate synthase
• Enzyme engineering
• Mycobacterium tuberculosis

alpha-Isopropylmalate synthase (IPMS) catalyses the reaction between alpha-ketoisovalerate and acetyl coenzyme A (AcCoA) in the first step of leucine biosynthesis. IPMS is closely related to homocitrate synthase, which catalyses the reaction between AcCoA and the unbranched alpha-ketoacid alpha-ketoglutarate. Analysis of these enzymes suggests that several differently conserved key residues are responsible for the different substrate selectivity. These residues were systematically substituted in the Mycobacterium tuberculosis IPMS, resulting in changes in substrate specificity. A variant of IPMS was constructed with a preference for the unbranched alpha-ketoacids alpha-ketobutyrate and pyruvate over the natural branched substrate alpha-ketoisovalerate.

• 出版日期2014-5-2