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POLYMORPHIC POSTTRANSLATIONAL MODIFICATION OF ALKALINE PHOSPHATASE IN ESCHERICHIA COLI
Author(s) -
Dykhuizen Daniel E.,
Mudd Christy,
Honeycutt Ann,
Hartl Daniel L.
Publication year - 1985
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.1985.tb04075.x
Subject(s) - biology , escherichia coli , isozyme , alkaline phosphatase , biochemistry , gene , gene product , mutant , phosphatase , microbiology and biotechnology , enzyme , gel electrophoresis , gene expression
Natural isolates of Escherichia coli have been examined by polyacrylamide gel electrophoresis for variant isozyme patterns of alkaline phosphatase. The polypeptide chains of this enzyme normally exist in two forms—an unmodified polypeptide product of the phoA gene and a posttranslationally modified version of the same polypeptide that has had its N‐terminal arginine removed through the action of the iap gene product. These two forms of the polypeptide aggregate as dimers and thus normally form three electrophoretically distinguishable alkaline phosphatase isozymes. Among 104 strains screened, three had variant isozyme patterns. Two of these were deficient in the posttranslationally modified polypeptide, and cotransduction with cysI indicates that they carry mutant iap genes. The third variant is deficient in the unmodified form of the polypeptide. These results provide an unambiguous case of polymorphic posttranslational modification in E. coli .