Two mutant alleles ofmukB, a gene essential for chromosome partition inEscherichia coli

The MukB protein is essential for chromosome partitioning in Escherichia coli and consists of 1484 amino acid residues (170 kDa). We have determined the base changes at the mutated sites of the mukB106 mutant and a newly isolated mutant, mukB33. These mutant mukB genes were each found to carry a single base-pair transition which leads to an amino acid substitution; a serine residue at position 33 was changed to phenylalanine in the case of mukB106, and an aspartic acid residue at position 1201 was changed to asparagine in the case of mukB33.