TY - JOUR
T1 - The reduced levels of χ recognition exhibited by the RecBC1004D enzyme reflect its recombination defect in vivo
AU - Arnold, D. A.
AU - Bianco, P. R.
AU - Kowalczykowski, S. C.
PY - 1998/6/26
Y1 - 1998/6/26
N2 - Homologous recombination in Escherichia coli is initiated by the RecBCD enzyme and is stimulated by an 8-nucleotide element known as Chi (χ). We present a detailed biochemical characterization of a mutant RecBCD enzyme, designated RecBC1004D, that displays a reduced level of χ site recognition. Initially characterized genetically as unable to respond to the χ sequence, we provide evidence to indicate that the ability of this mutant enzyme to respond to χ is reduced rather than lost; the mutant displays about 20-fold lower χ recognition than wild-type RecBCD enzyme. Although this enzyme exhibits wild-type levels of double-stranded DNA exonuclease, helicase, and ATPase activity, its ability to degrade single-stranded DNA is enhanced 2-3-fold. The data presented here suggest that the reduced recombination proficiency of the recBC1004D strain observed in vivo results from a basal level of modification of the RecBC1004D enzyme at both χ-specific, as well as nonspecific, DNA sequences.
AB - Homologous recombination in Escherichia coli is initiated by the RecBCD enzyme and is stimulated by an 8-nucleotide element known as Chi (χ). We present a detailed biochemical characterization of a mutant RecBCD enzyme, designated RecBC1004D, that displays a reduced level of χ site recognition. Initially characterized genetically as unable to respond to the χ sequence, we provide evidence to indicate that the ability of this mutant enzyme to respond to χ is reduced rather than lost; the mutant displays about 20-fold lower χ recognition than wild-type RecBCD enzyme. Although this enzyme exhibits wild-type levels of double-stranded DNA exonuclease, helicase, and ATPase activity, its ability to degrade single-stranded DNA is enhanced 2-3-fold. The data presented here suggest that the reduced recombination proficiency of the recBC1004D strain observed in vivo results from a basal level of modification of the RecBC1004D enzyme at both χ-specific, as well as nonspecific, DNA sequences.
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U2 - 10.1074/jbc.273.26.16476
DO - 10.1074/jbc.273.26.16476
M3 - Article
C2 - 9632715
AN - SCOPUS:0032569030
VL - 273
SP - 16476
EP - 16486
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 26
ER -