1T2T

Crystal structure of the DNA-binding domain of intron endonuclease I-TevI with operator site

Summary for 1T2T

• Entry DOI: 10.2210/pdb1t2t/pdb
• Related: 1I3J
• Descriptor: 5'-D(*TP*TP*TP*GP*TP*AP*GP*GP*AP*CP*TP*GP*CP*CP*CP*TP*TP*TP*AP*AP*T)-3', 5'-D(*AP*AP*TP*TP*AP*AP*AP*GP*GP*GP*CP*AP*GP*TP*CP*CP*TP*AP*CP*AP*A)-3', Intron-associated endonuclease 1, ... (5 entities in total)
• Functional Keywords: protein-dna complex, hydrolase-dna complex, hydrolase/dna
• Biological source: Enterobacteria phage T4
• Total number of polymer chains: 3
• Total formula weight: 26191.01

Authors

Edgell, D.R.,Derbyshire, V.,Van Roey, P.,LaBonne, S.,Stanger, M.J.,Li, Z.,Boyd, T.M.,Shub, D.A.,Belfort, M. (deposition date: 2004-04-22, release date: 2004-09-07, Last modification date: 2023-08-23)

Primary citation

Edgell, D.R.,Derbyshire, V.,Van Roey, P.,LaBonne, S.,Stanger, M.J.,Li, Z.,Boyd, T.M.,Shub, D.A.,Belfort, M.
Intron-encoded homing endonuclease I-TevI also functions as a transcriptional autorepressor.
Nat.Struct.Mol.Biol., 11:936-944, 2004

PubMed Abstract: Customary binding sites of intron-encoded homing endonucleases lie within cognate intronless alleles, at the so-called homing sites. Here, we describe a novel, high-affinity binding site for I-TevI endonuclease, encoded within the group I td intron of phage T4. This site is an operator that overlaps the T4 late promoter, which drives I-TevI expression from within the td intron. I-TevI binds the operator and homing sites with equal affinity, and functions as a transcriptional autorepressor. Distinct sequence and spacing requirements of the catalytic domain result in reduced cleavage activity on operator DNA. Crystallographic studies showed that the overall interactions of the DNA-binding domain with the operator and homing sites are similar, but have some different hydrogen-bonding contacts. We present a model in which the flexibility in protein-DNA interactions allows I-TevI to bind variant intronless alleles to promote intron mobility while facilitating its function in autorepression, and thereby persistence in its host.

PubMed: 15361856
DOI: 10.1038/nsmb823

Experimental method

X-RAY DIFFRACTION (2.5 Å)