High-resolution structure of an engineered Cro monomer shows changes in conformation relative to the native dimer.
A rationally designed, genetically engineered, monomeric form of the Cro protein from bacteriophage lambda has been crystallized and its structure determined by isomorphous replacement and refined to a resolution of 1.54 A. The structure confirms the rationale of the design but, at the same time, reveals 1-2 A shifts throughout the monomer structure relative to the previously determined structure of the dimeric wild-type protein. These changes include a 1.6 A main-chain shift in part of the beta-sheet region of the molecule relative to the alpha-helical region and a 1.1 A shift of a buried phenylalanine within the core as well as a correlated 2.2 A shift in a solvent-exposed beta-hairpin. The conformational adjustments appear to reflect an inherent flexibility of the protein that is associated with its DNA-binding function.
Institute of Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene 97403, USA.
R A
RA
Albright
M C
MC
Mossing
B W
BW
Matthews
D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins; D011487:Protein Conformation; D015202:Protein Engineering; D017433:Protein Structure, Secondary; D012097:Repressor Proteins / Q000737:chemistry* / Q000378:metabolism; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins
D004268:DNA-Binding Proteins; D012097:Repressor Proteins; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins; D004247:DNA