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Relating primary structure to function in the Escherichia coli XerD site‐specific recombinase
Author(s) -
Spiers Andrew J.,
Sherratt David J.
Publication year - 1997
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1997.4171784.x
Subject(s) - recombinase , biology , dna , synapsis , site specific recombination , binding site , amino acid , integrases , biochemistry , flp frt recombination , genetics , recombination , plasmid , genetic recombination , gene
XerC and XerD are related 298‐amino‐acid site‐specific recombinases, each of which is responsible for the exchange of one pair of strands in Xer recombination. Both recombinases encode functions necessary for sequence‐specific DNA‐binding, co‐operative XerC/D interactions, synapsis and catalysis. These functions were related to the primary amino acid sequence by constructing and analysing internal and C‐terminal XerD deletions. An XerD derivative containing residues 1–233 was proficient in specific DNA binding, but did not interact co‐operatively with XerC. Deletion of a further five C‐terminal amino acids abolished binding to DNA. Proteins deleted for residues 32–88 and for residues 145–159 were deficient in DNA binding. Deletion of residues 244–281, a region containing amino acids necessary for catalysis, gave a protein that bound to DNA. An XerD derivative containing residues 1–268 retained co‐operative interactions with XerC; nevertheless, it did not support XerC strand exchange and was defective in XerD catalysis. Residues 1–283 retain a functional catalytic active site, though a protein lacking the five C‐terminal amino acids was still unable to mediate normal in vivo recombination, indicating that these residues are needed for a function that is not directly related to DNA binding or catalysis.