5e63

K262A mutant of I-SmaMI

spinqualitylabelsall models 5e63, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5e63 is a 5 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: MG, MXE, PG0 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Publication Abstract from PubMed LAGLIDADG homing endonucleases ("meganucleases") are highly specific DNA cleaving enzymes that are used for genome engineering. Like other enzymes that act on DNA targets, meganucleases often display binding affinities and cleavage activities that are dominated by one protein domain. To decipher the underlying mechanism of asymmetric DNA recognition and catalysis, we identified and characterized a new monomeric meganuclease (I-SmaMI), which belongs to a superfamily of homologous enzymes that recognize divergent DNA sequences. We solved a series of crystal structures of the enzyme-DNA complex representing a progression of sequential reaction states, and we compared the structural rearrangements and surface potential distributions within each protein domain against their relative contribution to binding affinity. We then determined the effects of equivalent point mutations in each of the two enzyme active sites to determine whether asymmetry in DNA recognition is translated into corresponding asymmetry in DNA cleavage activity. These experiments demonstrate the structural basis for "dominance" by one protein domain over the other and provide insights into this enzyme's conformational switch from a nonspecific search mode to a more specific recognition mode. The Structural Basis of Asymmetry in DNA Binding and Cleavage as Exhibited by the I-SmaMI LAGLIDADG Meganuclease.,Shen BW, Lambert A, Walker BC, Stoddard BL, Kaiser BK J Mol Biol. 2015 Dec 15. pii: S0022-2836(15)00696-8. doi:, 10.1016/j.jmb.2015.12.005. PMID:26705195 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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