Mechanism for Fluorescence Quenching of Tryptophan by Oxamate and Pyruvate: Conjugation and Solvation-Induced Photoinduced Electron Transfer.

ABSTRACT: Oxamate and pyruvate are isoelectronic molecules. They both quench tryptophan fluorescence with Stern-Volmer constants of 16 and 20 M^-1, respectively, which are comparable to that of arcrylamide, a commonly used probe for protein structure. On the other hand, it is well known that neither the carboxylate group of these molecules nor the amide group is a good quencher. To find the mechanism of the quenching by oxamate and pyruvate, density functional theory computations with a polarizable continuum model, solvation based on density, and explicit waters, were performed. Results indicate that both molecules can be an electron acceptor via photoinduced electron transfer. There are two requirements. First, the carboxylate and amide moieties must be in direct contact to bring about no

SUBMITTER: Peng HL 

PROVIDER: S-EPMC6038119 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature