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| - | [[Image:2ecs.jpg|left|200px]] | + | {{Seed}} |
| | + | [[Image:2ecs.png|left|200px]] |
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| | {{STRUCTURE_2ecs| PDB=2ecs | SCENE= }} | | {{STRUCTURE_2ecs| PDB=2ecs | SCENE= }} |
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| - | '''Lambda Cro mutant Q27P/A29S/K32Q at 1.4 A in space group C2'''
| + | ===Lambda Cro mutant Q27P/A29S/K32Q at 1.4 A in space group C2=== |
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| - | ==Overview==
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| - | 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.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_18054042}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 18054042 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_18054042}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Helix-turn-helix]] | | [[Category: Helix-turn-helix]] |
| | [[Category: Transcription factor]] | | [[Category: Transcription factor]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 02:20:35 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 06:14:28 2008'' |
Revision as of 03:14, 29 July 2008
Template:STRUCTURE 2ecs
Lambda Cro mutant Q27P/A29S/K32Q at 1.4 A in space group C2
Template:ABSTRACT PUBMED 18054042
About this Structure
2ECS is a Single protein structure of sequence from Enterobacteria phage lambda. Full crystallographic information is available from OCA.
Reference
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
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