Heterogeneity in the structural dynamics of Sulfolobus solfataricus beta-glycosidase revealed by electron paramagnetic resonance and frequency domain fluorometry.

ABSTRACT: The local and global dynamics of the Sulfolobus solfataricus beta-glycosidase were studied by electron spin resonance and time-resolved fluorescence techniques. For electron paramagnetic resonance (EPR) investigations, the protein was covalently modified by the maleimido nitroxide spin label, which is specific for cysteine -SH groups, at position 344 and at position 101, where Ser-101 was changed into a cysteine by site-directed mutagenesis. The greater reactivity of exposed Cys-101 suggested the exclusive modification of this amino acid compared with Cys-344. The labeled proteins underwent temperature perturbation in the range 290-335 K and the values of the spin-label rotation correlation frequencies (nu(c)) ranged from 6 x 10(7) to 2 x 10(8) sec(-1) for the protein labeled at position C

SUBMITTER: Lozinsky E 

PROVIDER: S-EPMC2373732 | biostudies-literature | 2002 Nov

REPOSITORIES: biostudies-literature