Determination of the solution-bound conformation of an amino acid binding protein by NMR paramagnetic relaxation enhancement: use of a single flexible paramagnetic probe with improved estimation of its sampling space.

ABSTRACT: We demonstrate the feasibility of elucidating the bound ("closed") conformation of a periplasmic binding protein, the glutamine-binding protein (GlnBP), in solution, using paramagnetic relaxation enhancements (PREs) arising from a single paramagnetic group. GlnBP consists of two globular domains connected by a hinge. Using the ligand-free ("open") conformation as a starting point, conjoined rigid-body/torsion-angle simulated annealing calculations were performed using backbone (1)H(N)-PREs as a major source of distance information. Paramagnetic probe flexibility was accounted for via a multiple-conformer representation. A conventional approach where the entire PRE data set is enforced at once during simulated annealing yielded poor results due to inappropriate conformational sampling of th

SUBMITTER: Bermejo GA 

PROVIDER: S-EPMC2720827 | biostudies-literature | 2009 Jul

REPOSITORIES: biostudies-literature