Kinetic, crystallographic, and mechanistic characterization of TomN: elucidation of a function for a 4-oxalocrotonate tautomerase homologue in the tomaymycin biosynthetic pathway.

ABSTRACT: The biosynthesis of the C ring of the antitumor antibiotic agent, tomaymycin, is proposed to proceed through five enzyme-catalyzed steps from l-tyrosine. The genes encoding these enzymes have recently been cloned and their functions tentatively assigned, but there is limited biochemical evidence supporting the assignments of the last three steps. One enzyme, TomN, shows 58% pairwise sequence similarity with 4-oxalocrotonate tautomerase (4-OT), an enzyme found in a catabolic pathway for aromatic hydrocarbons. The TomN sequence includes three amino acids (Pro-1, Arg-11, and Arg-39) that have been identified as critical catalytic residues in 4-OT. However, the proposed substrate for TomN is very different from that processed by 4-OT. To establish the function and mechanism of TomN and its rel

SUBMITTER: Burks EA 

PROVIDER: S-EPMC3164527 | biostudies-literature | 2011 Sep

REPOSITORIES: biostudies-literature