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Crystal structure of Ca<sup>2+</sup>/H<sup>+</sup> antiporter protein YfkE reveals the mechanisms of Ca<sup>2+</sup> efflux and its pH regulation

Crystal structure of Ca2+/H+ antiporter protein YfkE reveals the mechanisms of Ca2+ efflux and its pH regulation

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Prüfsumme: MD5:d227c85172174e6a6b9f0decfda3d120

WU, Mousheng, Shuilong TONG, Sandro WALTERSPERGER, Kay DIEDERICHS, Meitian WANG, Lei ZHENG, 2013. Crystal structure of Ca2+/H+ antiporter protein YfkE reveals the mechanisms of Ca2+ efflux and its pH regulation. In: Proceedings of the National Academy of Sciences. 110(28), pp. 11367-11372. ISSN 0027-8424. eISSN 1091-6490. Available under: doi: 10.1073/pnas.1302515110

@article{Wu2013-07-09Cryst-26310, title={Crystal structure of Ca2+/H+ antiporter protein YfkE reveals the mechanisms of Ca2+ efflux and its pH regulation}, year={2013}, doi={10.1073/pnas.1302515110}, number={28}, volume={110}, issn={0027-8424}, journal={Proceedings of the National Academy of Sciences}, pages={11367--11372}, author={Wu, Mousheng and Tong, Shuilong and Waltersperger, Sandro and Diederichs, Kay and Wang, Meitian and Zheng, Lei} }

Waltersperger, Sandro Proceedings of the National Academy of Sciences of the United States of America : PNAS ; 110 (2013), 28. - S. 11367-11372 Tong, Shuilong Wang, Meitian 2014-02-07T13:50:23Z Wu, Mousheng Wang, Meitian Tong, Shuilong Zheng, Lei eng deposit-license Diederichs, Kay Waltersperger, Sandro Zheng, Lei 2013-07-09 Diederichs, Kay 2014-02-07T13:50:23Z Wu, Mousheng Ca<sup>2+</sup> efflux by Ca<sup>2+</sup> cation antiporter (CaCA) proteins is important for maintenance of Ca<sup>2+</sup> homeostasis across the cell membrane. Recently, the monomeric structure of the prokaryotic Na<sup>+</sup>/Ca<sup>2+</sup> exchanger (NCX) antiporter NCX_Mj protein from Methanococcus jannaschii shows an outward-facing conformation suggesting a hypothesis of alternating substrate access for Ca<sup>2+</sup> efflux. To demonstrate conformational changes essential for the CaCA mechanism, we present the crystal structure of the Ca<sup>2+</sup>/H<sup>+</sup> antiporter protein YfkE from Bacillus subtilis at 3.1-Å resolution. YfkE forms a homotrimer, confirmed by disulfide crosslinking. The protonated state of YfkE exhibits an inward-facing conformation with a large hydrophilic cavity opening to the cytoplasm in each protomer and ending in the middle of the membrane at the Ca<sup>2+</sup>-binding site. A hydrophobic “seal” closes its periplasmic exit. Four conserved α-repeat helices assemble in an X-like conformation to form a Ca<sup>2+</sup>/H<sup>+</sup> exchange pathway. In the Ca2+-binding site, two essential glutamate residues exhibit different conformations compared with their counterparts in NCX_Mj, whereas several amino acid substitutions occlude the Na<sup>+</sup>-binding sites. The structural differences between the inward-facing YfkE and the outward-facing NCX_Mj suggest that the conformational transition is triggered by the rotation of the kink angles of transmembrane helices 2 and 7 and is mediated by large conformational changes in their adjacent transmembrane helices 1 and 6. Our structural and mutational analyses not only establish structural bases for mechanisms of Ca<sup>2+</sup>/H<sup>+</sup> exchange and its pH regulation but also shed light on the evolutionary adaptation to different energy modes in the CaCA protein family. Crystal structure of Ca<sup>2+</sup>/H<sup>+</sup> antiporter protein YfkE reveals the mechanisms of Ca<sup>2+</sup> efflux and its pH regulation

Dateiabrufe seit 01.10.2014 (Informationen über die Zugriffsstatistik)

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