Repressor of phage 16-3 with altered binding specificity indicates spatial differences in repressor-operator complexes.
The C repressor protein of phage 16-3, which is required for establishing and maintaining lysogeny, recognizes structurally different operators which differ by 2 bp in the length of the spacer between the conserved palindromic sequences. A "rotationally flexible protein homodimers" model has been proposed in order to explain the conformational adaptivity of the 16-3 repressor. In this paper, we report on the isolation of a repressor mutant with altered binding specificity which was used to identify a residue-base pair contact and to monitor the spatial relationship of the recognition helix of C repressor to the contacting major groove of DNA within the two kinds of repressor-operator complexes. Our results indicate spatial differences at the interface which may reflect different docking arrangements in recognition of the structurally different operators by the 16-3 repressor.
Ferenczi
Szilamér
S
Institute of Genetics, Agricultural Biotechnology Center, Gödöllõ, Szent-Györgyi A. 4., H-2100, Hungary.
Orosz
László
L
Papp
Péter P
PP
D001435:Bacteriophages / Q000378:metabolism* / Q000502:physiology; D001665:Binding Sites; D008242:Lysogeny; D009875:Operator Regions, Genetic; D011485:Protein Binding; D011487:Protein Conformation; D012097:Repressor Proteins / Q000737:chemistry / Q000378:metabolism*; D016962:Sinorhizobium meliloti / Q000821:virology; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*
D012097:Repressor Proteins; D014764:Viral Proteins