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Titolo:
HETERODIMERIZATION OF THE YEAST HOMEODOMAIN TRANSCRIPTIONAL REGULATORS ALPHA-2 AND A1 INDUCES AN INTERFACIAL HELIX IN ALPHA-2
Autore:
PHILLIPS CL; STARK MR; JOHNSON AD; DAHLQUIST FW;
Indirizzi:
UNIV OREGON,INST MOLEC BIOL EUGENE OR 97403 UNIV OREGON,INST MOLEC BIOL EUGENE OR 97403 UNIV CALIF SAN FRANCISCO,DEPT MICROBIOL & IMMUNOL SAN FRANCISCO CA 94143
Titolo Testata:
Biochemistry
fascicolo: 31, volume: 33, anno: 1994,
pagine: 9294 - 9302
SICI:
0006-2960(1994)33:31<9294:HOTYHT>2.0.ZU;2-5
Fonte:
ISI
Lingua:
ENG
Soggetto:
NUCLEAR-MAGNETIC-RESONANCE; H COUPLING-CONSTANTS; HOMEO-DOMAIN; NMR-SPECTROSCOPY; REPRESSOR ALPHA-2; CRYSTAL-STRUCTURE; DNA INTERACTIONS; PROTEIN; BINDING; PROTON;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
41
Recensione:
Indirizzi per estratti:
Citazione:
C.L. Phillips et al., "HETERODIMERIZATION OF THE YEAST HOMEODOMAIN TRANSCRIPTIONAL REGULATORS ALPHA-2 AND A1 INDUCES AN INTERFACIAL HELIX IN ALPHA-2", Biochemistry, 33(31), 1994, pp. 9294-9302

Abstract

The homeodomain proteins a1 and alpha 2 act cooperatively to regulatecell type specific genes in yeast. The basis of the cooperativity is a weak interaction between the two proteins which forms heterodimers that bind DNA tightly and specifically. In this paper, we examine the mechanism of heterodimerization. We show that two relatively small fragments of a1 and alpha 2 are capable of heterodimerization and tight DNA binding. The alpha 2 fragment contains the homeodomain followed by the natural 22 C-terminal amino acids of the protein; these 22 amino acids are unstructured in the alpha 2 fragment. The a1 fragment containsonly the homeodomain, indicating that the a1 homeodomain mediates both DNA binding and protein-protein interactions with alpha 2. We used isotope-edited NMR spectroscopy to study the interaction in solution ofthese two fragments. Samples in which only the alpha 2 fragment was uniformly labeled with N-15 allowed us to visualize changes in the NMR spectra of the alpha 2 fragment produced by heterodimerization. We found that the a1 homeodomain perturbs the resonances of only the C-terminal tail of alpha 2; moreover, contact with a1 converts a portion of this tail (residues 193-203) from its unstructured state to an alpha-helix, as determined by J coupling and NOE measurements. Thus the heterodimerization of two homeodomain proteins involves the specific interaction between a tail of one protein and the homeodomain of the other. This interaction is accompanied by the acquisition of secondary structure in the tail.

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Documento generato il 05/07/20 alle ore 09:28:00