Sequence-specific proton NMR resonance assignments of Bacillus subtilus HPr: use of spectra obtained from mutants to resolve spectral overlap

Abstract

On the basis of an analysis of two-dimensional 1H NMR spectra, the complete sequence-specific 1H NMR assignments are presented for the prosphocarrier protein HPr from the Gram-positive bacterium Bacillus subtilis. During the assignment procedure, extensive use was made of spectra obtained from point mutants of HPr in order to resolve spectral overlap and to provide verification of assignments. Regions of regular secondary structure were identified by characteristic patterns of sequential backbone proton NOEs and slowly exchanging amide protons. B. subtilis HPr contains four .beta.-strands that form a single antiparallel .beta.-sheet and two well-define .alpha.-helices. There are two stretches of extended backbone structure, one of which contains the active site His15. The overall fold of the protein is very similar to that of Escherchia coli HPr determined by NMR studies [Klevit, R. E., and Waygood, E. B. (1986) Biochemistry 25, 7774-7781].