Intron-encoded homing endonuclease I-TevI also functions as a transcriptional autorepressor.
Nat Struct Mol Biol
; 11(10): 936-44, 2004 Oct.
Article
em En
| MEDLINE
| ID: mdl-15361856
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.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Repressoras
/
Íntrons
/
Endodesoxirribonucleases
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Nat Struct Mol Biol
Ano de publicação:
2004
Tipo de documento:
Article