Gin invertase of bacteriophage Mu is a dimer in solution, with the domain for dimerization in the N-terminal part of the protein.
The Gin protein of bacteriophage Mu mediates recombination between two inverted repeat sequences. Gin binds as a dimer to each of these recombination sites. We show that Gin is a dimer in solution also, and that the dimerization is probably stabilized by hydrophobic interactions between the subunits. The subunits of the dimer could efficiently be cross-linked with the 4-A cross-linker diepoxybutane. Spontaneous oxidation of Cys(24) and/or Cys(27) also resulted in intersubunit cross-linking. One or both cysteine residues are located at the interface of the Gin dimer, which maps the dimerization domain in the N-terminal part of the protein. Binding of the disulfide-bonded dimers of Gin to a recombination site was strongly reduced, suggesting that the subunits need to reorient in order to form a stable protein-DNA complex. In the protein-DNA complex, however, oxidation of cysteine residues still seems to be possible, indicating that the N-terminal parts of two Gin subunits are also in close proximity when bound to DNA.
Laboratory of Molecular Genetics, Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, The Netherlands.
L
L
Spaeny-Dekking
M
M
van Hemert
P
P
van de Putte
N
N
Goosen
D000595:Amino Acid Sequence; D010583:Bacteriophage mu / Q000737:chemistry*; D004254:DNA Nucleotidyltransferases / Q000737:chemistry*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D012091:Repetitive Sequences, Nucleic Acid
D004254:DNA Nucleotidyltransferases; C056830:DNA invertase Gin