Multicopy suppressors of prc mutant Escherichia coli include two HtrA (DegP) protease homologs (HhoAB), DksA, and a truncated RlpA
Multicopy suppressors of prc mutant Escherichia coli include two HtrA (DegP) protease homologs (HhoAB), DksA, and a truncated RlpA
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DOI：
10.1128/jb.178.4.1154-1161.1996
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发表时间：
1996-02-01
影响因子：
3.2
通讯作者：
Christen, A
中科院分区：
文献类型：
--
作者：
Bass, S;Gu, QM;Christen, A
我们已经分离出三个多拷贝抑制剂的条件致死表型的一个PRC（TSP）空菌株的大肠杆菌。这些抑制因子之一包括两个新的推定蛋白酶基因串联映射到3400 kb或72.5 centisomes的染色体上。我们建议的名称hhoA和hhoB，为htrA同源物，表示这些基因编码的蛋白质是58和35%相同，分别为HtrA（DegP）丝氨酸蛋白酶和36%相同。预测HhoA和HhoB蛋白的长度分别为455和355个氨基酸。成熟的HhoA蛋白是周质的位置，氨基末端测序表明，它产生后切割的27个氨基酸的信号肽。对蛋白质和DNA数据库的分析揭示了在各种其他细菌中迅速增长的同源基因家族，包括在其宿主中毒力所需的几个基因。hhoAB基因的缺失表明，它们不像同源htrA那样是高温下生存所必需的，但比野生型菌株生长更慢。第二个多拷贝前抑制基因是dksA（dnaK抑制基因），它也是热休克基因dnaK、dnaJ和grpE缺陷的多拷贝抑制基因。dksA基因作为mukB突变的多拷贝抑制基因独立分离，这是染色体分区所需的。第三种剂量依赖性prc抑制因子包括截短的稀有脂蛋白A（rlpA）基因。
We have isolated three multicopy suppressors of the conditional lethal phenotype of a prc (tsp) null strain of Escherichia coli. One of these suppressors included two novel putative protease genes in tandem that map to 3400 kb or 72.5 centisomes on the chromosome. We propose the names hhoA and hhoB, for htrA homolog, to denote that these genes encode proteins that are 58 and 35% identical, respectively, to the HtrA (DegP) serine protease and 36% identical to each other. The HhoA and HhoB proteins are predicted to be 455 and 355 amino acids, respectively, in length. The mature HhoA protein is periplasmic in location, and amino-terminal sequencing shows that it arises following cleavage of a 27-amino-acid signal peptide. Searches of the protein and DNA databases reveal a rapidly growing family of homologous genes in a variety of other bacteria, including several which are required for virulence in their host. Deletion of the hhoAB genes shows that they are not required for viability at high temperatures like the homologous htrA but grow more slowly than wild-type strains. A second multicopy pre suppressor is the dksA (dnaK suppressor) gene, which is also a multicopy suppressor of defects in the heat shock genes dnaK, dnaJ, and grpE. The dksA gene was independently isolated as a multicopy suppressor of a mukB mutation, which is required for chromosomal partitioning. A third dosage-dependent prc suppressor includes a truncated rare lipoprotein A (rlpA) gene.