Solution Structure and Calcium-Binding Properties of M-Crystallin, A Primordial βY-Crystallin from Archaea
Solution Structure and Calcium-Binding Properties of M-Crystallin, A Primordial βY-Crystallin from Archaea
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DOI：
10.1016/j.jmb.2008.12.058
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发表时间：
2009-02-27
影响因子：
5.6
通讯作者：
Chary, Kandala V. R.
中科院分区：
文献类型：
--
作者：
Barnwal, Ravi Pratap;Jobby, M. K.;Chary, Kandala V. R.
晶状体β-γ-晶体蛋白超家族有许多不同但在拓扑上相关的成员，它们属于不同的类群。根据结构拓扑学，这些蛋白质被认为与晶状体晶体蛋白在进化上有亲缘关系，表明它们起源于共同的祖先。虽然在一些真核生物和真细菌中发现了含有晶体蛋白结构域的蛋白质，但在古生菌中尚未见报道。对古细菌甲烷链霉菌基因组的序列搜索发现，存在一种被注释为β-伽马晶体蛋白家族蛋白的蛋白质，名为M-晶体蛋白。该蛋白质的溶液结构显示了一个典型的β-晶体蛋白折叠，并带有成对的希腊-键基序。在已知的β-晶状体蛋白结构中，M-晶状体蛋白与脊椎动物晶状体中的β-晶状体蛋白结构相似。这种原始蛋白质的钙结合特性与脊椎动物的β-γ-晶体蛋白比细菌的同系物更相似。综上所述，这些观察结果表明，两栖动物和脊椎动物的β-晶体蛋白结构域在进化上更多地与古生物同源物有关，而不是与细菌同源物有关。此外，在古生菌中鉴定β-伽马晶体蛋白同源物使我们能够证明该结构域在生命的所有三个领域中的存在。(C)2008爱思唯尔有限公司。保留所有权利。
The lens beta gamma-crystallin superfamily has many diverse but topologically related members belonging to various taxa. Based on structural topology, these proteins are considered to be evolutionarily related to lens crystallins, suggesting their origin from a common ancestor. Proteins with crystallin domains, although found in some eukaryotes and eubacteria, have not yet been reported in archaea. Sequence searches in the genome of the archaebacterium Methanosarcina acetivorans revealed the presence of a protein annotated as a beta gamma-crystallin family protein, named M-crystallin. Solution structure of this protein indicates a typical beta gamma-crystallin fold with a paired Greek-key motif. Among the known structures of beta gamma-crystallin members, M-crystallin was found to be structurally similar to the vertebrate lens beta gamma-crystallins. The Ca2+-binding properties of this primordial protein are somewhat more similar to those of vertebrate beta gamma-ycrystallins than to those of bacterial homologues. These observations, taken together, suggest that amphibian and vertebrate beta gamma-crystallin domains are evolutionarily more related to archaeal homologues than to bacterial homologues. Additionally, identification of a beta gamma-crystallin homologue in archaea allows us to demonstrate the presence of this domain in all the three domains of life. (c) 2008 Elsevier Ltd. All rights reserved.