This is a competitive renewal application to provide continued support for collaborative studies on the enzymatic mechanisms of tyrosine phenol-lyase. This enzyme uses 5'-periodical phosphate (PLP) as a cofactor, and it is involved in several amino acid modification reactions including transaminations, decarboxylations and beta and gamma eliminations. Several biologically active metabolites involved in a variety of important biological processes, including neurotransmission, depend on similar enzymes. In the present studies the collaborators will continue on their previous course and will generate three dimensional structures of wild-type tyrosine phenol-lyase with substrates and substrate analogs. The structural results of these studies will guide additional experiments for the generation of variant forms of the enzyme. In addition, kinetic studies using multiple isotope effects will be done to identify the rate limiting step in tyrosine phenol-lyase mediated catalysis.
| Demidkina, T V; Faleev, N G; Papisova, A I et al. (2006) Aspartic acid 214 in Citrobacter freundii tyrosine phenol-lyase ensures sufficient C--H-acidity of the external aldimine intermediate and proper orientation of the cofactor at the active site. Biochim Biophys Acta 1764:1268-76 |
| Kulikova, Vitalia V; Zakomirdina, Ludmila N; Dementieva, Irene S et al. (2006) Tryptophanase from Proteus vulgaris: the conformational rearrangement in the active site, induced by the mutation of Tyrosine 72 to phenylalanine, and its mechanistic consequences. Biochim Biophys Acta 1764:750-7 |
