Salmonella typhimurium mutants defective in flagellar filament regrowth and sequence similarity of FliI to F0F1, vacuolar, and archaebacterial ATPase subunits.
Salmonella typhimurium mutants defective in flagellar filament regrowth and sequence similarity of FliI to F0F1, vacuolar, and archaebacterial ATPase subunits.
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鼠伤寒沙门氏菌突变体在鞭毛丝再生和 FliI 与 F0F1、液泡和古细菌 ATP 酶亚基的序列相似性方面存在缺陷。
DOI：
10.1128/jb.173.11.3564-3572.1991
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发表时间：
1991
影响因子：
3.2
通讯作者：
Macnab,RM
中科院分区：
文献类型：
--
作者：
Vogler,AP;Homma,M;Irikura,VM;Macnab,RM
许多鞭毛蛋白是通过鞭毛特有的输出途径输出的。在最初试图确定负责这一过程的装置的特征时，我们设计了一种简单的方法来筛选具有出口缺陷的突变。将鼠伤寒沙门氏菌的温度敏感鞭毛突变体在允许温度(30℃)下生长，然后移至限制温度(42℃)，在光学显微镜下观察。除了开关突变体外，它们都是完全能动的。接下来，在允许的温度下生长的细胞在移动到限制的温度之前，通过剪切去除它们的鞭毛细丝。大多数突变体都能再生花丝。然而，flhA、fliH、fliI和flin突变体没有或显著减少了再生长，这表明相应的基因产物参与了鞭毛特异性输出的过程。我们在这里描述了fliH、fliI和邻近的基因fliJ的序列，它们编码的蛋白质分子量分别为25、782、49、208和17,302 Da。FliI的推导序列与细菌F0F1 ATPase的催化β亚基以及空泡和考古细菌ATPase的催化亚基有很大的相似性；除了组成核苷酸结合或催化位点的基序有有限的相似性外，它似乎与E1E2类ATPase无关，与其他介导蛋白质输出的蛋白质或其他各种利用ATP的酶无关。我们假设FliI要么是鞭毛特异输出的蛋白质转位酶的催化亚单位，要么是参与鞭毛局部回路的质子转位酶。
Many flagellar proteins are exported by a flagellum-specific export pathway. In an initial attempt to characterize the apparatus responsible for the process, we designed a simple assay to screen for mutants with export defects. Temperature-sensitive flagellar mutants of Salmonella typhimurium were grown at the permissive temperature (30 degrees C), shifted to the restrictive temperature (42 degrees C), and inspected in a light microscope. With the exception of switch mutants, they were fully motile. Next, cells grown at the permissive temperature had their flagellar filaments removed by shearing before the cells were shifted to the restrictive temperature. Most mutants were able to regrow filaments. However, flhA, fliH, fliI, and fliN mutants showed no or greatly reduced regrowth, suggesting that the corresponding gene products are involved in the process of flagellum-specific export. We describe here the sequences of fliH, fliI, and the adjacent gene, fliJ; they encode proteins with deduced molecular masses of 25,782, 49,208, and 17,302 Da, respectively. The deduced sequence of FliI shows significant similarity to the catalytic beta subunit of the bacterial F0F1 ATPase and to the catalytic subunits of vacuolar and archaebacterial ATPases; except for limited similarity in the motifs that constitute the nucleotide-binding or catalytic site, it appears unrelated to the E1E2 class of ATPases, to other proteins that mediate protein export, or to a variety of other ATP-utilizing enzymes. We hypothesize that FliI is either the catalytic subunit of a protein translocase for flagellum-specific export or a proton translocase involved in local circuits at the flagellum.