Allosteric transitions of the maltose transporter studied by an elastic network model
Allosteric transitions of the maltose transporter studied by an elastic network model
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DOI：
10.1002/bip.22455
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发表时间：
2014-07
期刊：
影响因子：
2.9
通讯作者：
Chun Hua Li;Yong Xiao Yang;J. Su;B. Liu;J. Tan;X. Zhang;Cunxin Wang
中科院分区：
文献类型：
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作者：
Chun Hua Li;Yong Xiao Yang;J. Su;B. Liu;J. Tan;X. Zhang;Cunxin Wang
来自大肠杆菌的麦芽糖转运蛋白是一种三磷酸腺苷结合盒(ABC)转运蛋白，它利用三磷酸腺苷水解酶的能量将底物转移到细胞膜上。到2011年为止，麦芽糖转运蛋白在运输过程中的不同状态已经确定了三种晶体结构。基于这些晶体结构，应用自适应各向异性网络模型，研究了从静止态(向内)到催化中间态(向外)的变构路径。结果表明，变构转变是以耦合的方式进行的。首先发生核苷酸结合域的关闭，然后这种构象变化通过EAA和EAS环传播到跨膜域(TMD)，然后传播到麦芽糖结合蛋白，这有助于麦芽糖的移位。还发现TMD中存在非刚体运动和不对称运动。细胞质门可能只在预易位向外转换的过程中起变构传播的作用。此外，结果表明，螺旋结构域向类RecA结构域的移动主要发生在转变的早期阶段。这些结果可以为理解ABC转运蛋白的机制提供一些启示。©2013威利期刊，Inc.生物聚合物101：758-768,2014。
The maltose transporter from Escherichia coli is one of the ATP‐binding cassette (ABC) transporters that utilize the energy from ATP hydrolysis to translocate substrates across cellular membranes. Until 2011, three crystal structures have been determined for maltose transporter at different states in the process of transportation. Here, based on these crystal structures, the allosteric pathway from the resting state (inward‐facing) to the catalytic intermediate state (outward‐facing) is studied by applying an adaptive anisotropic network model. The results suggest that the allosteric transitions proceed in a coupled way. The closing of the nucleotide‐binding domains occurs first, and subsequently this conformational change is propagated to the transmembrane domains (TMD) via the EAA and EAS loops, and then to the maltose‐binding protein, which facilitates the translocation of the maltose. It is also found that there exist nonrigid‐body and asymmetric movements in the TMD. The cytoplasmic gate may only play the role of allosteric propagation during the transition from the pretranslocation to outward‐facing states. In addition, the results show that the movment of the helical subdomain towards the RecA‐like subdomain mainly occurs in the earlier stages of the transition. These results can provide some insights into the understanding of the mechanism of ABC transporters. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 758–768, 2014.