Work

Intracellular p H modulates quinary structure

Year: 2015

Type: article

Abstract: NMR spectroscopy can provide information about proteins in living cells. pH is an important characteristic of the intracellular environment because it modulates key protein properties such as net charge and stability. Here, we show that pH modulates quinary interactions, the weak, ubiquitous interactions between proteins and other cellular macromolecules. We use the K10H variant of the B domain of protein G (GB1, 6.2 kDa) as a pH reporter in Escherichia coli cells. By controlling the intracellular pH, we show that quinary interactions influence the quality of in-cell (15) N-(1) H HSQC NMR spectra. At low pH, the quality is degraded because the increase in attractive interactions between E. coli proteins and GB1 slows GB1 tumbling and broadens its crosspeaks. The results demonstrate the importance of quinary interactions for furthering our understanding of protein chemistry in living cells.

Source: Protein Science

DOI: 10.1002/pro.2765

Authors: Rachel D. Cohen, Alex J. Guseman, Gary J. Pielak

Institutions: University of North Carolina at Chapel Hill, UNC Lineberger Comprehensive Cancer Center

Language: English

Topic: Advanced NMR Techniques and Applications

Subfield: Spectroscopy

Field: Chemistry

Domain: Physical Sciences

Open Access status: bronze

Funder: National Science Foundation

Award: Macromolecular crowding in vitro and in cells