|3e42, resolution 2.68Å ()|
|Gene:||hindIIR, HI0512 (Haemophilus influenzae)|
|Related:|| 3e41, 2gih, 3e3y, 3e40, 3e43, 3e44, 3e45
Q138F HincII bound to GTCGAC and Ca2+ (cocrystallized)
Five new structures of the Q138F HincII enzyme bound to a total of three different DNA sequences and three different metal ions (Ca(2+), Mg(2+), and Mn(2+)) are presented. While previous structures were produced from soaking Ca(2+) into preformed Q138F HincII/DNA crystals, the new structures are derived from cocrystallization with Ca(2+), Mg(2+), or Mn(2+). The Mn(2)(+)-bound structure provides the first view of a product complex of Q138F HincII with cleaved DNA. Binding studies and a crystal structure show how Ca(2+) allows trapping of a Q138F HincII complex with noncognate DNA in a catalytically incompetent conformation. Many Q138F HincII/DNA structures show asymmetry, despite the binding of a symmetric substrate by a symmetric enzyme. The various complexes are fit into a model describing the different conformations of the DNA-bound enzyme and show how DNA conformational energetics determine DNA-cleavage rates by the Q138F HincII enzyme.
DNA distortion and specificity in a sequence-specific endonuclease., Babic AC, Little EJ, Manohar VM, Bitinaite J, Horton NC, J Mol Biol. 2008 Oct 31;383(1):186-204. Epub 2008 Aug 22. PMID:18762194
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.