Purification and N-terminal amino acid sequences of two polypeptides encoded by the mcrB gene from Escherichia coli K-12.
This report provides a purification method for the two proteins, 51 kDa and 33 kDa, both encoded by the same mcrB gene of the McrBC restriction system in Escherichia coli K-12. The two proteins were produced in large quantity using a T7 expression system and copurified to near homogeneity by DEAE-Sepharose and Affi-Gel blue column chromatography. The N-terminal amino acid sequences of these purified McrB proteins were the same as those predicted from the mcrB DNA sequence by Ross et al. [J. Bacteriol. 171 (1989b) 1974-1981]. The 33-kDa protein totally overlaps the C-terminal part of the 51-kDa protein.
Zheng
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Department of Microbiology, Louisiana State University, Baton Rouge 70803.
Wang
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Braymer
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D000595:Amino Acid Sequence; D002845:Chromatography; D004262:DNA Restriction Enzymes / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D015257:DNA-Cytosine Methylases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D005822:Genetic Vectors / Q000235:genetics; D008969:Molecular Sequence Data; D013604:T-Phages / Q000235:genetics
D029968:Escherichia coli Proteins; C059683:DNA modification methylase McrB; D015257:DNA-Cytosine Methylases; D004262:DNA Restriction Enzymes; C059678:mcrB protein, E coli