Crystal structure of the soluble domain of the major anaerobically induced outer membrane protein (AniA) from pathogenic Neisseria:: A new class of copper-containing nitrite reductases
Crystal structure of the soluble domain of the major anaerobically induced outer membrane protein (AniA) from pathogenic Neisseria:: A new class of copper-containing nitrite reductases
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DOI：
10.1006/jmbi.2001.5251
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发表时间：
2002-02-01
影响因子：
5.6
通讯作者：
Murphy, MEP
中科院分区：
文献类型：
--
作者：
Boulanger, MJ;Murphy, MEP
致病性淋病奈瑟菌的主要厌氧诱导外膜蛋白(ANIA)是在亚硝酸盐存在的限氧条件下细胞生长所必需的，并对人血清的杀伤具有保护作用。系统发育分析表明，Ania是一类新的含铜亚硝酸盐还原酶的成员。ANIA可溶性结构域的表达产生了一种能够还原亚硝酸盐的蛋白质，其比活力为160U/mg，约为土壤反硝化菌粪产碱菌S-6亚硝酸盐还原酶测定值的50%。用分子置换和六重平均的方法确定了ANIA可溶域的晶体结构，其分辨率为2.4埃。亚硝酸盐浸泡的ANIA晶体结构细化到1.95埃，揭示了衬底与11型铜结合的双齿模式。尽管序列同源性很低(类似于30%)，但ANIA的核心铜还蛋白折叠与土壤细菌的含铜亚硝酸盐还原酶相似。主要的结构差异局限于两个减弱的表面环，这两个环映射到序列比对中的缺失。在土壤亚硝酸盐还原酶中，其中一个表面环位于I型铜位附近，为蛋白质类电子供体的对接表面贡献残基。在ANIA中，这种环的衰减导致重组的疏水结合表面，这可能是与脂质锚定的天青素相互作用所必需的。第二个衰减环位于ANIA的对侧，可以促进与脂膜的更紧密的相互作用。围绕SANIA第一类铜位的结构效应器的独特组合有助于产生不同寻常的可见吸收光谱，以前在绿色或蓝色第一类铜位观察到的成分。(C)2002年爱思唯尔科学有限公司。
The major anaerobically induced outer membrane protein (AniA) from pathogenic Neisseria gonorrhoeae is essential for cell growth under oxygen limiting conditions in the presence of nitrite and is protective against killing by human sera. A phylogenic analysis indicates that AniA is a member of a new class of copper-containing nitrite reductases. Expression of the soluble domain of AniA yields a protein capable of reducing nitrite with specific activity of 160 units/mg, approximately 50% of that measured for the nitrite reductase from the strong soil denitrifier Alcaligenes faecalis S-6. The crystal structure of the soluble domain of AniA was solved by molecular replacement and sixfold averaging to a resolution of 2.4 Angstrom. The nitrite soaked AniA crystal structure refined to 1.95 Angstrom reveals a bidentate mode of substrate binding to the type 11 copper. Despite low sequence identity (similar to30%), the core cupredoxin fold of AniA is similar to that found in copper-containing nitrite reductases from soil bacteria. The main structural differences are localized to two attenuated surface loops that map to deletions in the sequence alignment. In soil nitrite reductases, one of these surface loops is positioned near the type I copper site and contributes residues to the docking surface for proteaceous electron donors. In AniA, the attenuation of this loop results in a restructured hydrophobic binding surface that may be required to interact with a lipid anchored azurin. The second attenuated loop is positioned on the opposite side of AniA and may facilitate a more intimate interaction with the lipid membrane. A unique combination of structural effectors surrounding the type I copper site of sAnia contribute to a unusual visible absorption spectra with components observed previously in either green or blue type I copper sites. (C) 2002 Elsevier Science Limited.