The structure of the N62D mutant of the junction-resolving endonuclease VII (EndoVII) from phage T4 has been refined at 1.3 A, and a second wild-type crystal form solved and refined at 2.8 A resolution. Comparison of the mutant with the wild-type protein structure in two different crystal environments reveals considerable conformational flexibility at the dimer level affecting the substrate-binding cleft, the dimerization interface and the orientation of the C-terminal domains. The opening of the DNA-binding cleft, the orientation of the C-terminal domains relative to the central dimerization domain as well as the relative positioning of helices in the dimerization interface appear to be sensitive to the crystal packing environment. The highly unexpected rearrangement within the extended hydrophobic interface does change the contact surface area but keeps the number of hydrophobic contacts about the same and will therefore not require significant energy input. The conformational flexibility most likely is of functional significance for the broad substrate specificity of EndoVII. Binding of sulphate ions in the mutant structure and their positions relative to the active-site metal ions and residues known to be essential for catalysis allows us to propose a possible catalytic mechanism. A comparison with the active-site geometries of other magnesium-dependent nucleases, among them the homing endonuclease I-PpoI and Serratia endonuclease, shows common features, suggesting related catalytic mechanisms.
The line below this paragraph, {{ABSTRACT_PUBMED_11327769}}, adds the Publication Abstract to the page
(as it appears on PubMed at http://www.pubmed.gov), where 11327769 is the PubMed ID number.
-->
{{ABSTRACT_PUBMED_11327769}}
==About this Structure==
==About this Structure==
Line 31:
Line 35:
[[Category: Hydrolase]]
[[Category: Hydrolase]]
[[Category: Resolvase]]
[[Category: Resolvase]]
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 14:45:19 2008''
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 00:16:32 2008''
Revision as of 21:16, 30 June 2008
This article has been automatically seeded. Changes to this page should pertain to the PDB entry only and not to the protein or biomolecule in general.
