Intertwined structure of the DNA-binding domain of intron endonuclease I-TevI with its substrate
AUTOR(ES)
Van Roey, Patrick
FONTE
Oxford University Press
RESUMO
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 α-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.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=125541Documentos Relacionados
- The td intron endonuclease I-TevI makes extensive sequence-tolerant contacts across the minor groove of its DNA target.
- The td intron endonuclease I-TevI makes extensive sequence-tolerant contacts across the minor groove of its DNA target.
- Zinc finger as distance determinant in the flexible linker of intron endonuclease I-TevI
- I-TevI, the endonuclease encoded by the mobile td intron, recognizes binding and cleavage domains on its DNA target.
- Intron-encoded endonuclease I-TevI binds as a monomer to effect sequential cleavage via conformational changes in the td homing site.