Isolation of exonuclease VIII: the enzyme associated with sbcA indirect suppressor.
Proc Natl Acad Sci U S A
; 71(9): 3593-7, 1974 Sep.
Article
em En
| MEDLINE
| ID: mdl-4610579
ABSTRACT
recB and/or recC deficiency in Escherichia coli K-12 is indirectly suppressed by the presence of sbcA(-) mutations. sbcA(-) strains contain an increased level of an ATP-independent nuclease. Genetic and enzymatic tests indicate that this activity is not exonuclease III, exonuclease V (recB-recC nuclease), DNA polymerase I, or lambda exonuclease. This new enzyme (exonuclease VIII) has been purified 750-fold and shows a striking preference for double-stranded DNA over heat-denatured DNA. It does not act endonucleolytically on closed circular, single-stranded DNA as exonuclease V does. It also lacks a 3'-phosphatase function. Analysis on sodium dodecyl sulfate-polyacrylamide gels indicates that exonuclease VIII is not present in unsuppressed (sbcA(+)) strains. It is thought that sbcA determines some type of control function; the structural gene for exonuclease VIII is denoted by recE.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Recombinação Genética
/
Supressão Genética
/
Escherichia coli
/
Exonucleases
Tipo de estudo:
Risk_factors_studies
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
1974
Tipo de documento:
Article