1m5x
From Proteopedia
OCA (Talk | contribs)
(New page: 200px<br /><applet load="1m5x" size="450" color="white" frame="true" align="right" spinBox="true" caption="1m5x, resolution 2.25Å" /> '''Crystal structure of...)
Next diff →
Revision as of 01:42, 25 November 2007
|
Crystal structure of the homing endonuclease I-MsoI bound to its DNA substrate
Overview
Homing endonucleases are highly specific catalysts of DNA strand breaks, that induce the transposition of mobile intervening sequences containing, the endonuclease open reading frame. These enzymes recognize long DNA, targets while tolerating individual sequence polymorphisms within those, sites. Sequences of the homing endonucleases themselves diversify to a, great extent after founding intron invasion events, generating highly, divergent enzymes that recognize similar target sequences. Here, we, visualize the mechanism of flexible DNA recognition and the pattern of, structural divergence displayed by two homing endonuclease isoschizomers., We determined structures of I-CreI bound to two DNA target sites that, differ at eight of 22 base-pairs, and the structure of an isoschizomer, I-MsoI, bound to a nearly identical DNA target site. This study, illustrates several principles governing promiscuous base-pair recognition, by DNA-binding proteins, and demonstrates that the isoschizomers display, strikingly different protein/DNA contacts. The structures allow us to, determine the information content at individual positions in the binding, site as a function of the distribution of direct and water-mediated, contacts to nucleotide bases, and provide an evolutionary snapshot of, endonucleases at an early stage of divergence in their target specificity.
About this Structure
1M5X is a Single protein structure of sequence from Monomastix sp. with CA as ligand. Full crystallographic information is available from OCA.
Reference
Flexible DNA target site recognition by divergent homing endonuclease isoschizomers I-CreI and I-MsoI., Chevalier B, Turmel M, Lemieux C, Monnat RJ Jr, Stoddard BL, J Mol Biol. 2003 May 30;329(2):253-69. PMID:12758074
Page seeded by OCA on Sun Nov 25 03:49:45 2007
