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首页> 外文期刊>Biochemistry >Spectroscopic Characterization of Five-and Six-Coordinate Ferrous-NO Heme Complexes. Evidence for Heme Fe-Proximal Cysteinate Bond Cleavage in the Ferrous-NO Adducts of the Trp-409Tyr/Phe Proximal Environment Mutants of Neuronal Nitric Oxide Synthase
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Spectroscopic Characterization of Five-and Six-Coordinate Ferrous-NO Heme Complexes. Evidence for Heme Fe-Proximal Cysteinate Bond Cleavage in the Ferrous-NO Adducts of the Trp-409Tyr/Phe Proximal Environment Mutants of Neuronal Nitric Oxide Synthase

机译:五坐标铁血红素复合物的光谱表征。 血红素Fe-近端半胱氨酸粘连在铁核 - 409型/ phe近端环境突变体中的血红素Fe-近端半胱氨酸粘合粘膜的证据 - 神经元一氧化铬合酶

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摘要

Nitric oxide synthases (NOS) are a family of cysteine thiolate-ligated heme-containing monooxygenases that catalyze the NADPH-dependent two-step conversion of L-arginine to NO and L-citrulline. During the catalysis, a portion of the NOS heme forms an inhibitory complex with self-generated NO that is subsequently reverted back to No-free active enzyme under aerobic conditions, suggesting a downstream regualtor role of NO. Recent studies revealed that mutation of a conserved proximal tryptophan-409, which forms one of three hydrogen bonds to the heme-coordianted cysteine thiolate, to tyrosine or phenylalanine considerably increases the turnover number of neuronal NOS (nNOS). To further understand these properties of nNOS on its active site structural level, we have examined the oxygenase (heme-containing) domain of the two mutants in close comparison with that of wild-type nNOS with UV-visible absorption, magnetic circular dichroism, and electron paramagnetic resonance spectroscopy. Among several oxidation and ligation states examined, only the ferrous-NO adducts of the two mutants exhibit spectra that are markedly distinct from those of parallel derivatives of the wild-type protein. The spectra of the ferrous-NO mutants are broadly similar to those known five- coordinate ferrous-NO heme complexes, suggesting that these mutants are predominantly five coordiante in their ferrous-NO states. The present results are indicative of cleavage of the Fe-S bond in the nNOS mutants in their ferrous-NO state and imply a significant role of the conserved tryptophan in stabilization of the Fe-S bond.
机译:一氧化氮合成酶(NOS)是一家半胱氨酸硫醇硫酸盐连接血红素的单氧基酶,其催化L-精氨酸的NADPH依赖性两步转化为NO和L-瓜氨酸。在催化期间,NoS血红素的一部分形成抑制复合物,其自成的不产生的络合物,随后在有氧条件下再次恢复无无效的活性酶,表明NO的下游令人震惊的作用。最近的研究表明,保守的近端色氨酸-409的突变形成了三种氢键与血红素协调的半胱氨酸硫醇酯中的一种,对酪氨酸或苯丙氨酸相当增加了神经元NOS(NNOS)的成苗数量。为了进一步了解NNOS在其活性位点结构水平上的这些性质,我们研究了与具有UV可见吸收,磁性圆形二数分和磁性圆形二数分的野生型NNO的含氧酶(含血红素)结构域。电子顺磁共振光谱。在检查几种氧化和连接状态中,只有黑色 - 没有两种突变体的加合物表现出明显不同于野生型蛋白质的平行衍生物的光谱。黑色 - 无突变体的光谱与已知的五配位铁血红素复合物大致相似,表明这些突变体主要是其黑色金属态的五架构。目前的结果表明在铁陶瓷中的NNOS突变体中对Fe-S键的切割,并意味着保守色氨酸在稳定Fe-S债券中的显着作用。

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  • 来源
    《Biochemistry》 |2003年第8期|共10页
  • 作者单位

    Department of Chemistry and Biochemistry University of South Carolina 631 Sumter Street Columbia South Carolina 29208 Department of Immunology Lerner Research Institute Cleveland Clinic Foundation 9500 Euclid Avenue Cleveland Ohio 44195 Dep;

    Department of Chemistry and Biochemistry University of South Carolina 631 Sumter Street Columbia South Carolina 29208 Department of Immunology Lerner Research Institute Cleveland Clinic Foundation 9500 Euclid Avenue Cleveland Ohio 44195 Dep;

    Department of Chemistry and Biochemistry University of South Carolina 631 Sumter Street Columbia South Carolina 29208 Department of Immunology Lerner Research Institute Cleveland Clinic Foundation 9500 Euclid Avenue Cleveland Ohio 44195 Dep;

    Department of Chemistry and Biochemistry University of South Carolina 631 Sumter Street Columbia South Carolina 29208 Department of Immunology Lerner Research Institute Cleveland Clinic Foundation 9500 Euclid Avenue Cleveland Ohio 44195 Dep;

    Department of Chemistry and Biochemistry University of South Carolina 631 Sumter Street Columbia South Carolina 29208 Department of Immunology Lerner Research Institute Cleveland Clinic Foundation 9500 Euclid Avenue Cleveland Ohio 44195 Dep;

    Department of Chemistry and Biochemistry University of South Carolina 631 Sumter Street Columbia South Carolina 29208 Department of Immunology Lerner Research Institute Cleveland Clinic Foundation 9500 Euclid Avenue Cleveland Ohio 44195 Dep;

    Department of Chemistry and Biochemistry University of South Carolina 631 Sumter Street Columbia South Carolina 29208 Department of Immunology Lerner Research Institute Cleveland Clinic Foundation 9500 Euclid Avenue Cleveland Ohio 44195 Dep;

    Department of Chemistry and Biochemistry University of South Carolina 631 Sumter Street Columbia South Carolina 29208 Department of Immunology Lerner Research Institute Cleveland Clinic Foundation 9500 Euclid Avenue Cleveland Ohio 44195 Dep;

    Department of Chemistry and Biochemistry University of South Carolina 631 Sumter Street Columbia South Carolina 29208 Department of Immunology Lerner Research Institute Cleveland Clinic Foundation 9500 Euclid Avenue Cleveland Ohio 44195 Dep;

    Department of Chemistry and Biochemistry University of South Carolina 631 Sumter Street Columbia South Carolina 29208 Department of Immunology Lerner Research Institute Cleveland Clinic Foundation 9500 Euclid Avenue Cleveland Ohio 44195 Dep;

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  • 正文语种 eng
  • 中图分类 生物化学;
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