Fine tuning bacterial chemotaxis:: analysis of Rhodobacter sphaeroides behaviour under aerobic and anaerobic conditions by mutation of the major chemotaxis operons and cheY genes
Fine tuning bacterial chemotaxis:: analysis of Rhodobacter sphaeroides behaviour under aerobic and anaerobic conditions by mutation of the major chemotaxis operons and cheY genes
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DOI：
10.1093/emboj/19.17.4601
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发表时间：
2000-09-01
期刊：
影响因子：
11.4
通讯作者：
Armitage, JP
中科院分区：
文献类型：
--
作者：
Shah, DSH;Porter, SL;Armitage, JP
球形红细菌的趋化性比肠道细菌的趋化性复杂得多。球形红细菌具有多拷贝的趋化基因（两个cheA、一个切布、两个cheR、三个cheW、五个cheY但没有cheZ），控制单个“停止-启动”鞭毛，生长环境控制不同组基因的表达水平。对突变体的系留细胞分析表明，CheY（4）和CheY（5）是马达结合反应调节剂。组氨酸蛋白激酶CheA（2）通过CheY（4）介导引诱（“正常”）反应，而CheA（1）和CheY（5）似乎介导排斥（“反向”）反应。CheY（3）促进信号终止，可能作为磷酸盐库，尽管CheY（1）和CheY（2）可以替代。正常和反转的反应可以由独立的化学感受器组启动，其相对强度取决于生长条件。球形红细菌可能通过两种化学感受途径（在不同环境中以不同水平表达）使用拮抗反应，以维持其在当前最佳环境中的位置。复杂的趋化系统越来越多地被确定和R.sphaeroides采取的策略可能是常见的细菌王国。
Rhodobacter sphaeroides chemotaxis is significantly more complex than that of enteric bacteria. Rhodobacter sphaeroides has multiple copies of chemotaxis genes (two cheA, one cheB, two cheR, three cheW, five cheY but no cheZ), controlling a single 'stop-start' flagellum, The growth environment controls the level of expression of different groups of genes. Tethered cell analysis of mutants suggests that CheY(4) and CheY(5) are the motor-binding response regulators, The histidine protein kinase CheA(2) mediates an attractant ('normal') response via CheY(4), while CheA(1) and CheY(5) appear to mediate a repellent ('inverted') response. CheY(3) facilitates signal termination, possibly acting as a phosphate sink, although CheY(1) and CheY(2) can substitute. The normal and inverted responses may be initiated by separate sets of chemoreceptors with their relative strength dependent on growth conditions. Rhodobacter sphaeroides may use antagonistic responses through two chemosensory pathways, expressed at different levels in different environments, to maintain their position in a currently optimum environment. Complex chemotaxis systems are increasingly being identified and the strategy adopted by R.sphaeroides may be common in the bacterial kingdom.