Bukrinsky J T, Buch-Pedersen M J, Larsen S, Palmgren M G
Centre for Crystallographic Studies, Department of Chemistry, University of Copenhagen, Denmark.
FEBS Lett. 2001 Apr 6;494(1-2):6-10. doi: 10.1016/s0014-5793(01)02301-8.
We have used the 2.6 A structure of the rabbit sarcoplasmic reticulum Ca(2+)-ATPase isoform 1a, SERCA1a [Toyoshima, C., Nakasako, M., Nomura, H. and Ogawa, H. (2000) Nature 405, 647-655], to build models by homology modelling of two plasma membrane (PM) H(+)-ATPases, Arabidopsis thaliana AHA2 and Saccharomyces cerevisiae PMA1. We propose that in both yeast and plant PM H(+)-ATPases a strictly conserved aspartate in transmembrane segment (M)6 (D684(AHA2)/D730(PMA1)), and three backbone carbonyls in M4 (I282(AHA2)/I331(PMA1), G283(AHA2)/I332(PMA1) and I285(AHA2)/V334(PMA1)) comprise a binding site for H3O(+), suggesting a previously unknown mechanism for transport of protons. Comparison with the structure of the SERCA1a made it feasible to suggest a possible receptor region for the C-terminal auto-inhibitory domain extending from the phosphorylation and anchor domains into the transmembrane region.
我们利用兔肌浆网Ca(2+)-ATP酶同工型1a（SERCA1a）的2.6埃结构[丰岛，C.，中迫，M.，野村，H.和小川，H.（2000年）《自然》405，647 - 655]，通过同源建模构建了两种质膜（PM）H(+)-ATP酶的模型，即拟南芥AHA2和酿酒酵母PMA1。我们提出，在酵母和植物的质膜H(+)-ATP酶中，跨膜片段（M）6中一个严格保守的天冬氨酸（D684（AHA2）/D730（PMA1））以及M4中的三个主链羰基（I282（AHA2）/I331（PMA1）、G283（AHA2）/I332（PMA1）和I285（AHA2）/V334（PMA1））构成了一个H3O(+)结合位点，这表明存在一种此前未知的质子转运机制。与SERCA1a的结构进行比较，使得我们有可能提出一个从磷酸化和锚定结构域延伸至跨膜区域的C末端自身抑制结构域的可能受体区域。
