1i3j
From Proteopedia
CRYSTAL STRUCTURE OF THE DNA-BINDING DOMAIN OF INTRON ENDONUCLEASE I-TEVI WITH ITS SUBSTRATE
Overview
I-TevI is a site-specific, sequence-tolerant intron endonuclease. The crystal structure of the DNA-binding domain of I-TevI complexed with the 20 bp primary binding region of its DNA target reveals an unusually extended structure composed of three subdomains: a Zn finger, an elongated segment containing a minor groove-binding alpha-helix, and a helix-turn-helix. The protein wraps around the DNA, mostly following the minor groove, contacting the phosphate backbone along the full length of the duplex. Surprisingly, while the minor groove-binding helix and the helix-turn- helix subdomain make hydrophobic contacts, the few base-specific hydrogen bonds occur in segments that lack secondary structure and flank the intron insertion site. The multiple base-specific interactions over a long segment of the substrate are consistent with the observed high site specificity in spite of sequence tolerance, while the modular composition of the domain is pertinent to the evolution of homing endonucleases.
About this Structure
1I3J is a Single protein structure of sequence from Enterobacteria phage t4. Full crystallographic information is available from OCA.
Reference
Intertwined structure of the DNA-binding domain of intron endonuclease I-TevI with its substrate., Van Roey P, Waddling CA, Fox KM, Belfort M, Derbyshire V, EMBO J. 2001 Jul 16;20(14):3631-7. PMID:11447104 Page seeded by OCA on Fri May 2 19:31:46 2008
