一氧化氮、亚硝酸盐和Fnr监管hmp (flavohemoglobin)基因表达在大肠杆菌k - 12。
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普尔RK Anjum MF Membrillo-Hernandez J,金正日,休斯MN,斯图尔特V
一氧化氮、亚硝酸盐和Fnr监管hmp (flavohemoglobin)基因表达在大肠杆菌k - 12。
J Bacteriol。1996年9月,178 (18):5487 - 92。
- PubMed ID
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8808940 (在PubMed]
- 文摘
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大肠杆菌具有可溶性flavohemoglobin,未知函数,由高分子聚合物基因编码。包含一个monolysogen hmp-lacZ操纵子融合了hmp启动子是如何监管回应血红素配体(O2,没有)或厌氧的存在利用电子受体(硝酸盐、亚硝酸盐)。表达式的φ(hmp-lacZ) 1融合相似在有氧的增长基本培养基含有葡萄糖、甘油、麦芽糖、山梨糖醇作为碳源。突变自保”(编码腺苷酸环化酶)或5和9之间的介质pH值的变化没有影响有氧表达式。水平的有氧和厌氧glucose-containing最小的媒体的表达式是相同的;两人都不受影响的arcA突变。厌氧,但不是有氧,表达φ(hmp-lacZ) 1刺激fnr 3至4倍的突变;明显Fnr-binding hmp子站点存在。铁损耗丰富肉汤培养基的螯合剂2 ' 2 '联吡啶(0.1毫米)增强高分子聚合物表达式40倍在厌氧条件下,初步对Fnr归因于影响。在更高的螯合剂浓度(0.4毫米),hmp表达式也刺激了耗氧。 Anaerobic expression was stimulated 6-fold by the presence of nitrate and 25-fold by the presence of nitrite. Induction by nitrate or nitrite was unaffected by narL and/or narP mutations, demonstrating regulation of hmp by these ions via mechanisms alternative to those implicated in the regulation of other respiratory genes. Nitric oxide (10 to 20 microM) stimulated aerobic phi (hmp-lacZ)1 activity by up to 19-fold; soxS and soxR mutations only slightly reduced the NO effect. We conclude that hmp expression is negatively regulated by Fnr under anaerobic conditions and that additional regulatory mechanisms are involved in the responses to oxygen, nitrogen compounds, and iron availability. Hmp is implicated in reactions with small nitrogen compounds.