| Autor: |
Jeong BS; Department of Chemistry, Emory University , Atlanta, Georgia 30322, United States., Dyer RB; Department of Chemistry, Emory University , Atlanta, Georgia 30322, United States. |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of the American Chemical Society [J Am Chem Soc] 2017 May 17; Vol. 139 (19), pp. 6621-6628. Date of Electronic Publication: 2017 May 08. |
| DOI: |
10.1021/jacs.7b00617 |
| Abstrakt: |
The M2 proton transport channel of the influenza virus A is an important model system because it conducts protons with high selectivity and unidirectionally when activated at low pH, despite the relative simplicity of its structure. Although it has been studied extensively, the molecular details of the pH-dependent gating and proton conductance mechanisms are incompletely understood. We report direct observation of the M2 proton channel activation process using a laser-induced pH jump coupled with tryptophan fluorescence as a probe. Biphasic kinetics is observed, with the fast phase corresponding to the His37 protonation, and the slow phase associated with the subsequent conformation change. Unusually fast His37 protonation was observed (2.0 × 10 10 M -1 s -1 ), implying the existence of proton collecting antennae for expedited proton transport. The conformation change (4 × 10 3 s -1 ) was about 2 orders of magnitude slower than protonation at endosomal pH, suggesting that a transporter model is likely not feasible. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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