On the mechanism of inhibition of the neutrophil respiratory burst oxidase by a peptide from the C-terminus of the large subunit of cytochrome b558.
On the mechanism of inhibition of the neutrophil respiratory burst oxidase by a peptide from the C-terminus of the large subunit of cytochrome b558.
复制标题
细胞色素 b558 大亚基 C 末端肽抑制中性粒细胞呼吸爆发氧化酶的机制。
DOI：
10.1021/bi00002a017
复制
发表时间：
1995
期刊：
影响因子：
2.9
通讯作者：
Lambeth,JD
中科院分区：
文献类型：
--
作者：
Uhlinger,DJ;Tyagi,SR;Lambeth,JD
1994年9月13日收到的修订手稿？摘要：gp91-Phox的羧基末端(残基559-565)附近的一种肽(RGVHFIF)先前被证明能抑制呼吸爆发氧化酶的激活[Kleinberg，]。马利赫，HL和Rotrosen，D.(1990)J.化学。265、15577-15583]。该多肽被认为与gp91-Phox竞争结合到p47-Phox上，而p47-Phox是胞质氧化酶的一种成分。在目前的研究中，我们使用了一个由重组胞浆因子(p47-Phox、p67-Phox和racl)和分离的质膜组成的半重组系统来研究该肽抑制氧化酶激活的机制。在体外易位模型中，该肽抑制了花生四烯酸激活的P47-Phox和ç-Phox到质膜的易位。对抑制作用的动力学机制进行了探讨。抑制作用不仅对RAE和p61-Phox，而且对P47-Phox都是非竞争性的或混合抑制。我们认为，这种多肽不是竞争细胞色素-P47-Phox的相互作用，而是间接抑制，可能是通过结合和改变细胞色素？55的构象。抵抗微生物感染的主要宿主防御是由多形核白细胞(中性粒细胞)提供的。作为对微生物或可溶性刺激的反应，这些细胞最初产生超氧化物，然后在进入呼吸爆发的过程中产生其他活性氧中间体[在Lambeth(1988)中回顾]。超氧化物的产生是由NADPH依赖的呼吸爆发氧化酶启动的。该酶由细胞质和质膜两部分组成。胞浆蛋白包括P47-Phox、P67-Phox和一个小的GTP结合蛋白(rac1和/或rac2)，而膜上含有黄色素Bm，它由大亚基和小亚基组成，含有NADPH结合位点。P47-Phox和p67-Phox与细胞色素以1：1：1的比例组装(Uhlinger等人，1993年)
Revised Manuscript Received September 13, 1994® abstract: A peptide (RGVHFIF) from near the carboxyl terminus (residues 559—565) of gp9l-phox, the large subunit of cytochrome¿> 558, was previously shown to inhibit activation of the respiratory burst oxidase [Kleinberg,. E., Malech, HL, & Rotrosen, D.(1990) J. Biol. Chem. 265, 15577—15583]. The peptide has beenproposed to compete with gp91-phox binding to p47-phox, one of the cytosolic oxidase components. In the present studies, we have used a semirecombinant system consisting of recombinant cytosolic factors (p47-phox, p67-phox, and Racl) along with isolated plasma membrane to investigate the mechanism by which the peptide inhibits oxidase activation. In an in vitro translocation model, the peptide inhibited arachidonate-activated translocation of both p47-phox and ß-phox to the plasma membrane. The kinetic mechanism of inhibition was examined. Inhibition was noncompetitive or mixed with respectto not only Rae and p61-phox but alsoto p47-phox. We suggest that the peptide, rather than competing for cytochrome—p47-phox interactions, inhibits indirectly, perhaps by binding to and altering the conformation of cytochrome¿ 55s.The major host defense against microbial infection is provided by polymorphonuclear leukocytes (neutrophils). In response to microorganisms or soluble stimuli, these cells initially generate superoxide and, secondarily, other reactive oxygen intermediates in what has beentermed the respiratory burst [reviewed in Lambeth (1988)]. Superoxide generation is initiated by the NADPH-dependent respiratory burst oxidase. The enzyme consists of both cytosolic and plasma membrane components. The cytosolic proteins include p47-phox, p67-phox, and a small GTP-binding protein (Racl and/or Rac2), while the membrane contains flavocytochrome bm, which consists of both large and small subunits and contains the NADPH-binding site. p47-phox and p67-phox assemble in a 1: 1: 1 ratio with cytochrome (Uhlinger et al., 1993) in