Structure of homeodomain-leucine zipper/DNA complexes studied using hydroxyl radical cleavage of DNA and methylation interference.
Biochemistry
; 44(51): 16796-803, 2005 Dec 27.
Article
em En
| MEDLINE
| ID: mdl-16363793
Homeodomain-leucine zipper (HD-Zip) proteins, unlike most homeodomain proteins, bind a pseudopalindromic DNA sequence as dimers. We have investigated the structure of the DNA complexes formed by two HD-Zip proteins with different nucleotide preferences at the central position of the binding site using footprinting and interference methods. The results indicate that the respective complexes are not symmetric, with the strand bearing a central purine (top strand) showing higher protection around the central region and the bottom strand protected toward the 3' end. Binding to a sequence with a nonpreferred central base pair produces a decrease in protection in either the top or the bottom strand, depending upon the protein. Modeling studies derived from the complex formed by the monomeric Antennapedia homeodomain with DNA indicate that in the HD-Zip/DNA complex the recognition helix of one of the monomers is displaced within the major groove respective to the other one. This monomer seems to lose contacts with a part of the recognition sequence upon binding to the nonpreferred site. The results show that the structure of the complex formed by HD-Zip proteins with DNA is dependent upon both protein intrinsic characteristics and the nucleotides present at the central position of the recognition sequence.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
DNA
/
Zíper de Leucina
/
Radical Hidroxila
/
Proteínas de Homeodomínio
/
Metilação de DNA
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Biochemistry
Ano de publicação:
2005
Tipo de documento:
Article
País de afiliação:
Argentina
País de publicação:
Estados Unidos