Tryptophan rotamer distribution revealed for the α-helix in tear lipocalin by site-directed tryptophan fluorescence.

ABSTRACT: Rotamer libraries are a valuable tool for protein structure determination, modeling, and design. Site-directed tryptophan fluorescence (SDTF) was used in combination with the rotamer model for the fluorescence intensity decays to solve α-helical conformations of proteins in solution. Single Trp mutations located in an α-helical segment of human tear lipocalin were explored for structure assignment. Along with fluorescence λ(max) values, the rotamer model assignment of fluorescence lifetimes fits the backbone conformation. Typically, Trp fluorescence in proteins shows three lifetimes. However, for the α-helix, two lifetimes assigned to t and g(-) rotamers were satisfactory to describe Trp fluorescence intensity decays. The g(+) rotamer is not feasible in the α-helix due to steric restrictio

SUBMITTER: Gasymov OK 

PROVIDER: S-EPMC3517820 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature