PH-dependent picosecond structural dynamics in the distal pocket of nitrophorin 4 investigated by 2D IR spectroscopy.

ABSTRACT: Nitrophorin 4 (NP4) belongs to a family of pH-sensitive, nitric oxide (NO) transporter proteins that undergo a large structural change from a closed to an open conformation at high pH to allow for NO delivery. Measuring the pH-dependent structural dynamics in NP4-NO around the ligand binding site is crucial for developing a mechanistic understanding of NO binding and release. In this study, we use coherent two-dimensional infrared (2D IR) spectroscopy to measure picosecond structural dynamics sampled by the nitrosyl stretch in NP4-NO as a function of pH at room temperature. Our results show that both the closed and open conformers of the protein are present at low (pD 5.1) and high (pD 7.9) pH conditions. The closed and open conformers are characterized by two frequencies of the nitrosyl s

SUBMITTER: Cheng M 

PROVIDER: S-EPMC3909714 | biostudies-literature | 2013 Dec

REPOSITORIES: biostudies-literature