Open AccessCharacterization and Comparison of Chloramphenicol Acetyltransferase Variants
Author(s) -
ZAIDENZAIG Yeshayahu,
FITTON John E.,
PACKMAN Leonard C.,
SHAW William V.
Publication year - 1979
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1979.tb04208.x
Subject(s) - chloramphenicol acetyltransferase , chloramphenicol , acetyltransferase , biology , biochemistry , enzyme , agrobacterium tumefaciens , microbiology and biotechnology , genetics , gene , chemistry , antibiotics , transformation (genetics) , reporter gene , gene expression , acetylation
1 Variants of chloramphenicol acetyltransferase from a variety of bacterial species have been isolated and purified to homogeneity. They constitute a heterogeneous group of proteins as judged by analytical affinity and hydrophobic (‘detergent’) chromatography, native and sodium dodecyl sulfate electrophoresis, sensitivity to sulfhydryl specific reagents, steady state kinetic analysis, and reaction with antisera. 2 The most striking observation is that three variants of chloramphenicol acetyltransferase (R factor type III, Streptomyces acrimycini , and Agrobacterium tumefaciens ) possess an apparent subunit molecular weight (24500) which is significantly greater than that of all other variants examined (22500). The three atypical variants are not identical since they show marked differences in a number of important parameters. 3 Although the fundamental mechanism of catalysis may prove to be identical for all chloramphenicol acetyltransferase variants, there is a wide range of sensitivity to thiol‐directed inhibitors among the enzymes studied. 4 Amino acid sequence analysis of the N‐termini of selected variants suggests that the qualitative differences among chloramphenicol acetyltransferase variants is a reflection of structural heterogeneity which is most marked in comparisons between variants from Gram‐positive and Gram‐negative species.