THE NEW GENE MUKB CODES FOR A 177 KD PROTEIN WITH COILED-COIL DOMAINS INVOLVED IN CHROMOSOME PARTITIONING OF ESCHERICHIA-COLI
THE NEW GENE MUKB CODES FOR A 177 KD PROTEIN WITH COILED-COIL DOMAINS INVOLVED IN CHROMOSOME PARTITIONING OF ESCHERICHIA-COLI
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DOI：
10.1002/j.1460-2075.1991.tb07935.x
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发表时间：
1991-01-01
期刊：
影响因子：
11.4
通讯作者：
HIRAGA, S
中科院分区：
文献类型：
--
作者：
NIKI, H;JAFFE, A;HIRAGA, S
分离到一株能在低温下自发产生大小正常的无核细胞的大肠杆菌温度敏感突变株。该突变体存在一个此前未被描述的基因缺陷，名为mukB，位于染色体上的21分钟。MukB基因编码一个大蛋白(约180kd)。从mukB基因的核苷酸序列中推导出一个1534个氨基酸的蛋白质(176 826道尔顿)。计算机分析表明，预测的MukB蛋白具有不同的结构域：氨基末端球状结构域包含一个核苷酸结合序列，中心区域包含两个α螺旋卷曲结构域和一个球状结构域，以及一个羧基末端球状结构域，富含半胱氨酸、精氨酸和赖氨酸。通过电泳法在野生型细胞提取液中检测到的180kd蛋白在mukB缺失突变体中缺失。虽然零突变体在低温下不是致死的，但MukB的缺失会导致染色体的异常分裂。在高温下，mukB缺失突变体不能形成菌落，许多类核物质沿着细长的细胞不规则分布。我们的结论是，MukB蛋白是在大肠杆菌中进行染色体分割所必需的。
An Escherichia coli temperature sensitive mutant which produces spontaneously normal size anucleate cells at low temperature was isolated. The mutant is defective in a previously undescribed gene, named mukB, located at 21 min on the chromosome. The mukB gene codes for a large protein (approximately 180 kd). A 1534 amino acid protein (176 826 daltons) was deduced from the nucleotide sequence of the mukB gene. Computer analysis revealed that the predicted MukB protein has distinct domains: an amino-terminal globular domain containing a nucleotide binding sequence, a central region containing two alpha-helical coiled-coil domains and one globular domain, and a carboxyl-terminal globular domain which is rich in Cys, Arg and Lys. A 180 kd protein detected in wild-type cell extracts by electrophoresis is absent in mukB null mutants. Although the null mutants are not lethal at low temperature, the absence of MukB leads to aberrant chromosome partitioning. At high temperature the mukB null mutants cannot form colonies and many nucleoids are distributed irregularly along elongated cells. We conclude that the MukB protein is required for chromosome partitioning in E.coli.