Variability in the nucleic acid binding site size and the amount of single-stranded DNA-binding protein in Escherichia coli.
The Escherichia coli single-stranded DNA binding protein (SSB), essential for DNA replication, recombination and repair, can undergo a thermally induced irreversible conformational change which does not eliminate its biological activity, but changes the number of nucleotides it covers (binding site size) when binding to a single-stranded nucleic acid lattice. The binding site size of native and conformationally changed SSB was also found to be a function of the molecular mass of the polynucleotide, an observation which is unusual for single-stranded DNA binding proteins and will greatly affect the affinity relationship of this protein for nucleic acids. A radioimmunoassay used to quantitate in SSB level in cells revealed the number of SSB tetramers to be larger than initial estimates by a factor of as much as six. All these data suggest that the biological role of SSB and its mechanism of action is by far more complex than originally assumed.
Bobst
E V
EV
Bobst
A M
AM
Perrino
F W
FW
Meyer
R R
RR
Rein
D C
DC
D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000032:analysis*; D004578:Electron Spin Resonance Spectroscopy; D004926:Escherichia coli / Q000032:analysis*; D011487:Protein Conformation; D011863:Radioimmunoassay; D013056:Spectrophotometry, Ultraviolet; D013329:Structure-Activity Relationship
D004268:DNA-Binding Proteins