Probing tertiary structure of proteins using single Trp mutations with circular dichroism at low temperature.

ABSTRACT: Trp is the most spectroscopically informative aromatic amino acid of proteins. However, the near-UV circular dichroism (CD) spectrum of Trp is complicated because the intensity and sign of (1)La and (1)Lb bands vary independently. To resolve vibronic structure and gain site-specific information from complex spectra, deconvolution was combined with cooling and site-directed tryptophan substitution. Low temperature near-UV CD was used to probe the local tertiary structure of a loop and α-helix in tear lipocalin. Upon cooling, the enhancement of the intensities of the near-UV CD was not uniform, but depends on the position of Trp in the protein structure. The most enhanced (1)Lb band was observed for Trp at position 124 in the α-helix segment matching the known increased conformational mobili

SUBMITTER: Gasymov OK 

PROVIDER: S-EPMC3983331 | biostudies-literature | 2014 Jan

REPOSITORIES: biostudies-literature