Title
Structural basis of the bacteriophage TP901‐1 CI repressor dimerization and interaction with DNA
Author
Kim Krighaar Rasmussen, Anders K. Varming, Simon N. Schmidt, Kristian E.H. Frandsen, Peter W. Thulstrup, Malene Ringkjøbing Jensen, Leila Lo Leggio
Year
2018
Journal
FEBS Letters
Abstract
Temperate bacteriophages are known for their bi‐stability, which in TP901‐1 is controlled by two proteins, CI and MOR. CI is hexameric and binds three palindromic operator sites via an N‐terminal helix‐turn‐helix domain (NTD). A dimeric form, such as the truncated CI∆58 investigated here, is necessary for high affinity binding to DNA. The crystal structure of the dimerization region (CTD1) is determined here, showing that it forms a pair of helical hooks. This newly determined structure is used together with the known crystal structure of the CI‐NTD and small angle X‐ray scattering data, to determine the solution structure of CI∆58 in complex with a palindromic operator site, showing that the two NTDs bind on opposing sides of the DNA helix.
Instrument
J-815
Keywords
Circular dichroism, Secondary structure, DNA structure, DNA binding, Biochemistry