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The new gene mukB codes for a 177 kd protein with coiled‐coil domains involved in chromosome partitioning of E. coli.
Author(s) -
Niki H.,
Jaffé A.,
Imamura R.,
Ogura T.,
Hiraga S.
Publication year - 1991
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1991.tb07935.x
Subject(s) - biology , mutant , microbiology and biotechnology , coiled coil , gene , peptide sequence , temperature sensitive mutant , nucleic acid sequence , mutant protein , nucleoid , escherichia coli , genetics , biochemistry
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.