Cytochrome bd-I in Escherichia coli is less sensitive than cytochromes bd-II or bo'' to inhibition by the carbon monoxide-releasing molecule, CORM-3: N-acetylcysteine reduces CO-RM uptake and inhibition of respiration.
Cytochrome bd-I in Escherichia coli is less sensitive than cytochromes bd-II or bo'' to inhibition by the carbon monoxide-releasing molecule, CORM-3: N-acetylcysteine reduces CO-RM uptake and inhibition of respiration.
复制标题
DOI：
10.1016/j.bbapap.2013.04.019
复制
发表时间：
2013-09
影响因子：
3.2
通讯作者：
Poole, Robert K.
中科院分区：
文献类型：
--
作者：
Jesse, Helen E.;Nye, Tacita L.;McLean, Samantha;Green, Jeffrey;Mann, Brian E.;Poole, Robert K.
背景资料：一氧化碳释放分子（CO-RM）是一种潜在的治疗药物，能够在生物环境中释放一氧化碳-一种重要的气体递质。CO-RM也是有效的抗微生物剂;尽管作用机制尚不明确，但含血红素的末端氧化酶是主要靶点。然而，从几项研究中可以清楚地看出，CO-RM对生物系统的影响通常不能通过CO的释放来充分解释：CO-RM通常是比CO气体更有效的抑制剂，并且分子的其他影响是明显的。研究方法：因为对CO-RM的敏感性不能通过对CO气体的敏感性来预测，所以我们评估了菌株的差异敏感性，每个菌株仅表达E. CORM-3对大肠杆菌细胞色素bd-I、细胞色素bd-II和细胞色素bo′的抑制作用。我们提出了第一个灵敏的测量细胞色素bd-II的氧亲和力（Km 0.24 μM）采用珠蛋白脱氧。最后，我们研究了硫醇化合物消除CORM-2和CORM-3对呼吸、生长和活力的抑制作用的方式，这是一种有据可查但知之甚少的现象。结果如下：我们表明，菌株表达细胞色素bd-I作为唯一的氧化酶是最不容易受到CORM-3在其生长和呼吸的完整细胞和膜的抑制。生长研究表明，细胞色素bd-II对CORM-3的敏感性与细胞色素bo′相似。细胞色素bo′和bd-II对氧的亲和力也比bd-I低得多。我们表明，N-乙酰半胱氨酸消除CO-RM的毒性作用的能力是不归因于其抗氧化作用，或防止CO靶向氧化酶，但可能在很大程度上是由于抑制CO-RM吸收细菌细胞。结论：表达细胞色素bd-I作为唯一末端氧化酶的菌株对CORM-3的抑制最不敏感。N-乙酰半胱氨酸是E.杆菌一般意义：CO-RM的合理设计和开发需要对其活动有基本的了解。CO和CO-RM对哺乳动物和微生物细胞具有多方面的影响;在这里，我们表明E. coli对CORM-3的敏感性不同。这篇文章是题为“氧结合和传感蛋白”的特刊的一部分。细胞色素bd-I是大肠杆菌中一种对CORM不敏感的血红素蛋白。杆菌“第三氧化酶”细胞色素bd-II的氧亲和力较低（Km 0.24 μM）。非巯基抗氧化剂不能阻止CO-RM介导的呼吸抑制。N-乙酰半胱氨酸降低E.杆菌
Background: CO-releasing molecules (CO-RMs) are potential therapeutic agents, able to deliver CO – a critical gasotransmitter – in biological environments. CO-RMs are also effective antimicrobial agents; although the mechanisms of action are poorly defined, haem-containing terminal oxidases are primary targets. Nevertheless, it is clear from several studies that the effects of CO-RMs on biological systems are frequently not adequately explained by the release of CO: CO-RMs are generally more potent inhibitors than is CO gas and other effects of the molecules are evident. Methods: Because sensitivity to CO-RMs cannot be predicted by sensitivity to CO gas, we assess the differential susceptibilities of strains, each expressing only one of the three terminal oxidases of E. coli — cytochrome bd-I, cytochrome bd-II and cytochrome bo′, to inhibition by CORM-3. We present the first sensitive measurement of the oxygen affinity of cytochrome bd-II (Km 0.24 μM) employing globin deoxygenation. Finally, we investigate the way(s) in which thiol compounds abolish the inhibitory effects of CORM-2 and CORM-3 on respiration, growth and viability, a phenomenon that is well documented, but poorly understood. Results: We show that a strain expressing cytochrome bd-I as the sole oxidase is least susceptible to inhibition by CORM-3 in its growth and respiration of both intact cells and membranes. Growth studies show that cytochrome bd-II has similar CORM-3 sensitivity to cytochrome bo′. Cytochromes bo′ and bd-II also have considerably lower affinities for oxygen than bd-I. We show that the ability of N-acetylcysteine to abrogate the toxic effects of CO-RMs is not attributable to its antioxidant effects, or prevention of CO targeting to the oxidases, but may be largely due to the inhibition of CO-RM uptake by bacterial cells. Conclusions: A strain expressing cytochrome bd-I as the sole terminal oxidase is least susceptible to inhibition by CORM-3. N-acetylcysteine is a potent inhibitor of CO-RM uptake by E. coli. General significance: Rational design and exploitation of CO-RMs require a fundamental understanding of their activity. CO and CO-RMs have multifaceted effects on mammalian and microbial cells; here we show that the quinol oxidases of E. coli are differentially sensitive to CORM-3. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins. Cytochrome bd-I is a CORM- insensitive heme-protein in E. coli. The oxygen affinity of the ‘third oxidase’, cytochrome bd-II is low (Km 0.24 μM). Non-thiol antioxidants do not prevent CO-RM-mediated inhibition of respiration. N-acetylcysteine reduces the uptake of CORM-2 and CORM-3 by E. coli.
登录
查看更多内容
DOI：
10.1099/00221287-140-6-1395
发表时间：
1994-06-01
期刊：
MICROBIOLOGY-UK
影响因子：
--
作者：
DMELLO, R;HILL, S;POOLE, RK
通讯作者：
POOLE, RK
影响因子：
20.1
作者：
Clark, JE;Naughton, P;Motterlini, R
通讯作者：
Motterlini, R
影响因子：
4.1
作者：
CHEESMAN, MR;WATMOUGH, NJ;THOMSON, AJ
通讯作者：
THOMSON, AJ
影响因子：
2.9
作者：
BERGERSEN, FJ;TURNER, GL
通讯作者：
TURNER, GL
影响因子：
4.8
作者：
Gilberthorpe, Nicola J.;Poole, Robert K.
通讯作者：
Poole, Robert K.