期刊
BIOPHYSICAL JOURNAL
卷 92, 期 12, 页码 L103-L105出版社
CELL PRESS
DOI: 10.1529/biophysj.107.109165
关键词
-
类别
资金
- NCRR NIH HHS [RR06009, P41 RR006009] Funding Source: Medline
Structural characterization of the bacterial channel, AmtB, provides a glimpse of how members of its family might control the protonated state of permeant ammonium to allow for its selective passage across the membrane. In a recent study, we employed a combination of simulation techniques that suggested ammonium is deprotonated and reprotonated near dehydrative phenylalanine landmarks (F107 and F31, respectively) during its passage from the periplasm to the cytoplasm. At these landmarks, ammonium is forced to maintain a critical number (similar to 3) of hydrogen bonds, suggesting that the channel controls ammonium (de) protonation by controlling its coordination/hydration. In the work presented here, a free energy-based analysis of ammonium hydration in dilute aqueous solution indicates, explicitly, that at biological pH, the transition from ammonium (NH4+) to ammonia (NH3) occurs when these species are constrained to donate three hydrogen bonds or less. This result demonstrates the viability of the proposal that AmtB indirectly controls ammonium (de) protonation by directly controlling its hydration.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据