Mechanism of Chloramphenicol Resistance in Staphylococci: Characterization and Hybridization of Variants of Chloramphenicol Acetyltransferase
AUTOR(ES)
Sands, L. C.
RESUMO
Fifty clinical isolates of chloramphenicol-resistant staphylococci from diverse sources were screened for the presence of chloramphenicol acetyltransferase (CAT) and were found to contain the inducible chloramphenicol-inactivating enzyme in each case. Polyacrylamide disc gel electrophoresis revealed four distinct types of CAT of which three were purified to a state of homogeneity. Each purified CAT preparation was shown to exist as a tetrameric protein with a native molecular weight of 80,000 and an identical subunit size of 20,000. All four staphylococcal types of CAT exhibited identical catalytic and immunological properties, but they possessed variable sensitivity to heat denaturation and to inhibition by mercuric ion. Each of the three purified variants of staphylococcal CAT was capable of undergoing reversible denaturation in 6 m guanidine hydrochloride. In vitro hybridization was successful between pairs of each of the three purified staphylococcal enzymes. Only one heteromeric (hybrid) species was observed in addition to the parental types rather than the three predicted from the known quaternary structure of staphylococcal CAT.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=444403Documentos Relacionados
- Hybridization of Variants of Chloramphenicol Acetyltransferase Specified by fi+ and fi- R Factors
- Methicillin-resistant staphylococci: genetics and mechanisms of resistance.
- Methicillin resistance in staphylococci: molecular and biochemical basis and clinical implications.
- PENICILLIN-RESISTANT STAPHYLOCOCCI: MECHANISMS INVOLVED IN THE DEVELOPMENT OF RESISTANCE
- Characterization of Chloramphenicol Acetyltransferase from Chloramphenicol-resistant Staphylococcus aureus