BIOL 132 |
| The tyrosine aminomutase SgTAM catalyzes the formation of b-tyrosine in the biosynthetic pathway of the antitumor enediyne C-1027. SgTAM is homologous to the histidine ammonia lyase family of enzymes whose activity is dependent on the methylideneimidazole-5-one cofactor. Unlike the lyase enzymes, SgTAM catalyzes additional chemical transformations resulting in an overall 1,2 amino shift in the substrate a-tyrosine to generate b-tyrosine. The precise mechanistic role of methylideneimidazole-5-one in this novel family of aminomutases has not previously been established. We have solved the first X-ray crystal structure of a methylideneimidazole-5-one based aminomutase and this confirms the structural homology of SgTAM to ammonia lyases. Comparison of the structure of SgTAM to the tyrosine ammonia lyase from R. sphaeroides provides insight into the structural basis for aminomutase activity. Continuing biochemical and structural research provides evidence concerning the mechanism of aminomutase activity.
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Poster Session
8:00 PM-10:00 PM, Monday, August 20, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Biological Chemistry |
