Characterization of the CI repressor protein encoded by the temperate lactococcal phage TP901-1

TY - JOUR

T1 - Characterization of the CI repressor protein encoded by the temperate lactococcal phage TP901-1

AU - Pedersen, Margit

AU - Ligowska, Malgorzata

AU - Hammer, Karin

PY - 2010/4/15

Y1 - 2010/4/15

N2 - The gene regulatory mechanism determining the developmental pathway of the temperate bacteriophage TP901-1 is regulated by two phage-encoded proteins, CI and MOR. Functional domains of the CI repressor were investigated by introducing linkers of 15 bp at various positions in cI and by limited proteolysis of purified CI protein. We show that insertions of five amino acids at positions in the N-terminal half of CI resulted in mutant proteins that could no longer repress transcription from the lytic promoter, PL. We confirmed that the N-terminal domain of CI contains the DNA binding site, and we showed that this part of the protein is tightly folded, whereas the central part and the C-terminal part of CI seem to contain more flexible structures. Furthermore, insertions at several different positions in the central part of the CI protein reduced the cooperative binding of CI to the operator sites and possibly altered the interaction with MOR.

AB - The gene regulatory mechanism determining the developmental pathway of the temperate bacteriophage TP901-1 is regulated by two phage-encoded proteins, CI and MOR. Functional domains of the CI repressor were investigated by introducing linkers of 15 bp at various positions in cI and by limited proteolysis of purified CI protein. We show that insertions of five amino acids at positions in the N-terminal half of CI resulted in mutant proteins that could no longer repress transcription from the lytic promoter, PL. We confirmed that the N-terminal domain of CI contains the DNA binding site, and we showed that this part of the protein is tightly folded, whereas the central part and the C-terminal part of CI seem to contain more flexible structures. Furthermore, insertions at several different positions in the central part of the CI protein reduced the cooperative binding of CI to the operator sites and possibly altered the interaction with MOR.

U2 - 10.1128/JB.01387-09

DO - 10.1128/JB.01387-09

M3 - Journal article

C2 - 20118255

SN - 0021-9193

VL - 192

SP - 2102

EP - 2110

JO - Journal of Bacteriology

JF - Journal of Bacteriology

IS - 8

ER -