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首页> 外文期刊>Biochemistry >Factors Controlling the Reactivity of Hydrogen Sulfide with Hemeproteins
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Factors Controlling the Reactivity of Hydrogen Sulfide with Hemeproteins

机译：控制硫化氢与血红蛋白反应性的因素

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摘要

Hemoglobin I (HbI) from the clam Lucina pectinata is an intriguing hemeprotein that binds andntransports H2S to sulfide-oxidizing chemoautotrophic bacteria to maintain a symbiotic relationship and tonprotect the mollusk from H2S toxicity. Single point mutations at E7, B10, and E11 were introduced into thenHbI heme pocket to define the reactivity of sulfide with hemeproteins. The functional and structuralnproperties of mutant and wild-type recombinant proteins were first evaluated using the well-known ferrousnCO and O2 derivatives. The effects of these mutations on the ferric environment were then studied in thenmetaquo and hydrogen sulfide derivatives. The results obtained with the ferrous HbI mutants show that allnthe E7 substitutions and the PheB10Tyrmutation influence directly COandO2 binding and stability while thenB10 and E11 substitutions induce distal structural rearrangements that affect ligand entry and escapenindirectly. For the metaquo-GlnE7His, -PheB10Val, -PheB10Leu, and -E11 variants, two individualndistal structures are suggested, one ofwhich is associatedwithH-bonding interactions between the E7 residuesnand the bound water. Similar H-bonding interactions are invoked for these HbI-H2S mutant derivatives andnthe rHbI, altering in turn sulfide reactivity within these protein samples. This is evident in the resonancenRaman spectra of theseHbI-H2S complexes, which show reduction of heme iron as judged by the appearancenof the ν4 oxidation state marker at 1356 cm-1n, indicative of heme-FenIInspecies. This reduction processndepends strongly on distal mutations showing faster reduction for thoseHbI mutants exhibiting the strongestnH-bonding interactions. Overall, the results presented here show that (a) H2S association is regulated bynexternal kinetic barriers, (b) H2S release is controlled by two competing reactions involving simple sulfidendissociation and heme reduction, (c) at highH2S concentrations, reduction of the ferric center dominates, andn(d) reduction of the heme is also enhanced in those HbI mutants having polar distal environments
机译：来自蛤仔露琪娜的血红蛋白I（HbI）是一种吸引人的血红蛋白，它结合H2S并将其转运至硫化物氧化的化学自养细菌，从而维持共生关系并保护软体动物免受H2S毒性的侵害。将E7，B10和E11处的单点突变引入到当时的HbI血红素口袋中，以定义硫化物与血红蛋白的反应性。首先使用众所周知的亚铁CO和O2衍生物评估突变型和野生型重组蛋白的功能和结构性质。然后，在纳米和硫化氢衍生物中研究了这些突变对铁环境的影响。用亚铁HbI突变体获得的结果表明，Allnthe E7取代和PheB10Tyrmutation直接影响COandO2的结合和稳定性，而B10和E11取代则引起远端结构重排，从而影响配体的进入和间接逃逸。对于-GlnE7His，-PheB10Val，-PheB10Leu和-E11变体，建议了两个单独的结构，其中之一与E7残基和结合水之间的H键相互作用相关。这些HbI-H2S突变体衍生物和rHbI调用了类似的H键相互作用，从而改变了这些蛋白质样品中的硫化物反应性。这在这些HbI-H2S配合物的共振拉曼光谱中很明显，这表明血红素铁的减少，由1356 cm-1n处的ν4氧化态标记物的出现判断，表明血红素-FenIInspecies。该还原过程强烈依赖于远端突变，对于表现出最强的H-键相互作用的那些HbI突变体而言，远端突变显示出更快的还原。总体而言，此处显示的结果表明：（a）H2S的缔合受外部动力学障碍的调节，（b）H2S的释放受两个相互竞争的反应的控制，这些反应包括简单的硫键结合和血红素的还原，（c）在高H2S浓度下，铁中心的还原占主导地位，并且在具有极性远端环境的那些HbI突变体中，血红素的减少也得到增强

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  • 来源
    《Biochemistry》 |2009年第22期|p.4881-4894|共14页
  • 作者

    Ruth Pietri Ariel Lewis Ruth G. Leu0001 on Gullermina Casabona Laurent Kiger Syun-Ru Yeh;

  • 作者单位

    ‡Department of Chemistry, University of Puerto Rico, Mayag::uez Campus, P.O. Box 9019, Mayag::uez, Puerto Rico 00681-9019,§Department of Physiology and Biophysics, Albert Einstein College ofMedicine, 1300Morris Park Avenue, Bronx, New York 10461,) Department of Biochemistry, School ofMedicine, University of Puerto Rico,Medical Sciences Campus, P.O. Box 365067, San Juan,Puerto Rico 00936-5067,^Universidad Nacional de Quilmes, 1876 Bernal, Argentina, and @INSERM U779, University of Paris 11,H^ opital de Bicetre, 94275 Le Kremlin-Bicetre, France;

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