Without morphology, cryptic species stay in taxonomic crypsis following discovery
- 作者：Birgit C. Schlick-Steiner ; Bernhard Seifert ; Christian Stauffer ; Erhard Christian ; Ross H. Crozier ; Florian M. Steiner
- 关键词：PROTEINS
- 刊名：Trends in Ecology and Evolution
- 出版年：2007
- 期刊代码：148_01695347
- 类别：bio
- 出版时间：August 2007
- 卷：22
- 期：8
- 页码：391-392
- 文件大小：100 K
摘要
Molecular dynamics simulations of lactose permease (LacY) in a phospholipid bilayer reveal the conformational dynamics of the protein. In inhibitor-bound simulations (i.e., those closest to the X-ray structure) the protein was stable, showing little conformational change over a 50 ns timescale. Movement of the bound inhibitor, TDG, to an alternative binding mode was observed, so that it interacted predominantly with the N-terminal domain and with residue E269 from the C-terminal domain. In multiple ligand-free simulations, a degree of domain closure occurred. This switched LacY to a state with a central cavity closed at both the intracellular and periplasmic ends. This may resemble a possible intermediate in the transport mechanism. Domain closure occurs by a combination of rigid-body movements of domains and of intradomain motions of helices, especially TM4, TM5, TM10, and TM11. A degree of intrahelix flexibility appears to be important in the conformational change.