Two-dimensional 1H NMR studies of histidine-containing protein from Escherichia coli. 1. Sequential resonance assignments.

Two-dimensional NMR studies at 500 MHz have been performed on the histidine-containing protein (HPr) from Escherichia coli. HPr is one of the phosphocarrier proteins involved in the bacterial phosphoenolpyruvate:sugar phosphotransferase system that is responsible for the concomitant phosphorylation and translocation of a number of sugars. Sequential resonance assignments of HPr are complete. The conventional method of sequential assignments involving J-correlated spectroscopy (COSY) and nuclear Overhauser spectroscopy (NOESY) has been supplemented by optimized relayed coherence transfer spectroscopy (RELAY) to help overcome the spectral overlap that is inevitable in the spectra of proteins the size of HPr. RELAY experiments were performed in H2O to obtain NH-C beta H connectivities and in D2O to obtain C alpha H-C gamma H connectivities. The abundance of relayed coherence transfer peaks in the two experiments greatly aided in the assignment process of the complicated protein spectrum. The assignments lay the groundwork for the determination of the solution structure of HPr, as described in the accompanying paper [Klevit, R. E., & Waygood, E. B. (1986) Biochemistry (third paper of three in this issue)].