3MQY: Sgrai With Cleaved Dna And Magnesium Bound

SgrAI is a type II restriction endonuclease that cuts an unusually long recognition sequence and exhibits allosteric self-activation with expansion of DNA-sequence specificity. The three-dimensional crystal structures of SgrAI bound to cleaved primary-site DNA and Mg(2)(+) and bound to secondary-site DNA with either Mg(2)(+) or Ca(2)(+) are presented. All three structures show a conformation of enzyme and DNA similar to the previously determined dimeric structure of SgrAI bound to uncleaved primary-site DNA and Ca(2)(+) [Dunten et al. (2008), Nucleic Acids Res. 36, 5405-5416], with the exception of the cleaved bond and a slight shifting of the DNA in the SgrAI/cleaved primary-site DNA/Mg(2)(+) structure. In addition, a new metal ion binding site is located in one of the two active sites in this structure, which is consistent with proposals for the existence of a metal-ion site near the 3'-O leaving group.
PDB ID: 3MQYDownload
MMDB ID: 86444
PDB Deposition Date: 2010/4/28
Updated in MMDB: 2010/11
Experimental Method:
x-ray diffraction
Resolution: 2  Å
Source Organism:
synthetic construct
Similar Structures:
Biological Unit for 3MQY: hexameric; determined by author and by software (PISA)
Molecular Components in 3MQY
Label Count Molecule
Proteins (2 molecules)
Sgrair Restriction Enzyme
Molecule annotation
Nucleotides(2 molecules)
DNA (5'-d(*gp*ap*gp*tp*cp*cp*a)-3')
Molecule annotation
DNA (5'-d(p*cp*cp*gp*gp*tp*gp*gp*ap*cp*tp*c)-3')
Molecule annotation
Chemicals (6 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB