Solvation dynamics in protein environments: Comparison of fluorescence upconversion measurements of coumarin 153 in monomeric hemeproteins with molecular dynamics simulations

Mintu Halder, Iowa State University
Prasun Mukherjee, Iowa State University
Sayantan Bose, Iowa State University
Mark S. Hargrove, Iowa State University
Xueyu Song, Iowa State University
Jacob W. Petrich, Iowa State University

The following article appeared in Journal of Chemical Physics 127, 5 (2007): 055101 and may be found at doi: 10.1063/1.2753495.

Abstract

The complexes of the fluorescence probe coumarin 153 with apomyoglobin and apoleghemoglobin are used as model systems to study solvation dynamics in proteins.Time-resolved Stokes shift experiments are compared with molecular dynamics simulations, and very good agreement is obtained. The solvation of the coumarin probe is very rapid with approximately 60% occurring within 300fs and is attributed to interactions with water (or possibly to the protein itself). Differences in the solvation relaxation (or correlation) function C(t) for the two proteins are attributed to differences in their hemepockets