Structural highlights
Function
[RCRO_LAMBD] Cro represses genes normally expressed in early phage development and is necessary for the late stage of lytic growth. It does this by binding to the OL and OR operators regions normally used by the repressor protein for lysogenic maintenance.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
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.
Two structures of a lambda Cro variant highlight dimer flexibility but disfavor major dimer distortions upon specific binding of cognate DNA.,Hall BM, Roberts SA, Heroux A, Cordes MH J Mol Biol. 2008 Jan 18;375(3):802-11. Epub 2007 Nov 6. PMID:18054042[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Hall BM, Roberts SA, Heroux A, Cordes MH. Two structures of a lambda Cro variant highlight dimer flexibility but disfavor major dimer distortions upon specific binding of cognate DNA. J Mol Biol. 2008 Jan 18;375(3):802-11. Epub 2007 Nov 6. PMID:18054042 doi:10.1016/j.jmb.2007.10.082
