Abstract
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.
Original language | English |
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Pages (from-to) | 1071-1082 |
Number of pages | 12 |
Journal | Molecular Microbiology |
Volume | 24 |
Issue number | 5 |
DOIs | |
Publication status | Published - Jun 1997 |
Externally published | Yes |