Two-dimensional proton NMR studies of histidine-containing protein from Escherichia coli. 3. Secondary and tertiary structure as determined by NMR

Publisher Website
Google Scholar
Abstract
Sequence-specific resonance assignments of the 1H NMR spectrum of the 85-residue histidine-containing phosphocarrier protein (HPr) are complete [Klevit, R. E., Drobny, G. P., and Waygood, E. B. (1986) Biochemistry]. Additional side-chain assignments have been made with long-range coherence transfer experiments [Klevit, R. E. and Drobny, G. P. (1986) Biochemistry. In this paper, the NMR assignments were used to determine the secondary structure and the tertiary folding of HPr in solution. The secondary structural elements of the protein were determined by visual inspection of the pattern of nearest-neighbor nuclear Overhauser effects (NOEs) and the presence of persistent amide resonances. Escherichia coli HPr consists of four .beta.-strands, three .alpha.-helices, four reverse turns, and several regions of extended backbone structure. Long-range NOEs, especially among side-chain protons, were used to determine the tertiary structure of the protein by use of the secondary structural components. The four .beta.-strands form a single antiparallel .beta.-pleated sheet.The hydrophobic faces of the .alpha.-helices interact to form a hydrophobic core and sit above the hydrophobic face of the .beta.-sheet, forming an open-face .beta.-sheet sandwich structure. The active site histidine, His-15, is on a short kinked segment of backbone that is accessible to the solvent. The positively charged phosphorylation site (His-15 and Arg-17) interacts with the negatively charge carboxyl terminus of the protein (Glu-85). The resulting model of HPr was obtained without the use of a structure derived from X-ray diffraction studies and is the largest obtained thus far by two-dimensional NMR techniques.

This publication has 18 references indexed in Scilit: