All physiological processes are mediated by molecular recognition phenomena in aqueous media, utilizing highly specific interactions between molecules. The extraordinary specificity of an enzyme exemplifies the complex manner in which these interactions cooperate. To date, enzyme models have been used to study the interactions involved in catalysis, but have generally been to small to allow a complete investigation of the extended binding interactions involved in specific recognition processes. The use of an extended peptide-based model, to permit the exploration of binding interactions, is proposed. A further understanding of the interactions governing these recognition phenomena will provide insight into the manner with which life's processes are mediated. Orotidine 5'-monophosphate decarboxylase (ODCase) utilizes a rather unique mechanism to catalyze the last step in the essential pyrimidine biosynthetic pathway. An ODcase mimic that exploits the BBA structural motif reported by Imperiali, et. al will be constructed. This extended peptide motif will allow the exploration of specific substrate binding by providing the scaffold upon which to append an unnatural amino acid, possessing a 2,4-diaminopyrimidine side chain for recognition of the substrate. After synthesizing and incorporating this unnatural amino acid into the BBA structural motif via solid phase peptide synthesis, the substrate specificity of the resulting construct and its ability to catalyze decarboxylation will be assessed. A better understanding of the mechanism of ODcase could lead to the design of mechanism-based inhibitors and the development of effective anti-fungal, antibacterial, and anti-tumor chemotherapeutic agents.
| Kowalski, Jennifer A; Liu, Kai; Kelly, Jeffery W (2002) NMR solution structure of the isolated Apo Pin1 WW domain: comparison to the x-ray crystal structures of Pin1. Biopolymers 63:111-21 |
