2OVG

Lambda Cro Q27P/A29S/K32Q triple mutant at 1.35 A in space group P3221

Summary for 2OVG

• Entry DOI: 10.2210/pdb2ovg/pdb
• Related: 2ECS
• Descriptor: Phage lambda Cro, SULFATE ION, 4-(2-HYDROXYETHYL)-1-PIPERAZINE ETHANESULFONIC ACID, ... (4 entities in total)
• Functional Keywords: transcription factor, helix-turn-helix, bacteriophage, flexibility, transcription
• Biological source: Enterobacteria phage lambda
• Total number of polymer chains: 1
• Total formula weight: 7693.79

Authors

Hall, B.M.,Heroux, A.,Roberts, S.A.,Cordes, M.H. (deposition date: 2007-02-13, release date: 2008-01-08, Last modification date: 2023-08-30)

Primary citation

Hall, B.M.,Roberts, S.A.,Heroux, A.,Cordes, M.H.
Two structures of a lambda Cro variant highlight dimer flexibility but disfavor major dimer distortions upon specific binding of cognate DNA.
J.Mol.Biol., 375:802-811, 2008

PubMed Abstract: Previously reported crystal structures of free and DNA-bound dimers of lambda Cro differ strongly (about 4 A backbone rmsd), suggesting both flexibility of the dimer interface and induced-fit protein structure changes caused by sequence-specific DNA binding. Here, we present two crystal structures, in space groups P3(2)21 and C2 at 1.35 and 1.40 A resolution, respectively, of a variant of lambda Cro with three mutations in its recognition helix (Q27P/A29S/K32Q, or PSQ for short). One dimer structure (P3(2)21; PSQ form 1) resembles the DNA-bound wild-type Cro dimer (1.0 A backbone rmsd), while the other (C2; PSQ form 2) resembles neither unbound (3.6 A) nor bound (2.4 A) wild-type Cro. Both PSQ form 2 and unbound wild-type dimer crystals have a similar interdimer beta-sheet interaction between the beta1 strands at the edges of the dimer. In the former, an infinite, open beta-structure along one crystal axis results, while in the latter, a closed tetrameric barrel is formed. Neither the DNA-bound wild-type structure nor PSQ form 1 contains these interdimer interactions. We propose that beta-sheet superstructures resulting from crystal contact interactions distort Cro dimers from their preferred solution conformation, which actually resembles the DNA-bound structure. These results highlight the remarkable flexibility of lambda Cro but also suggest that sequence-specific DNA binding may not induce large changes in the protein structure.

PubMed: 18054042
DOI: 10.1016/j.jmb.2007.10.082

Experimental method

X-RAY DIFFRACTION (1.35 Å)