Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
SEPARATION OF INHIBITION AND ACTIVATION OF THE ALLOSTERIC YEAST CHORISMATE MUTASE
Autore:
SCHNAPPAUF G; LIPSCOMB WN; BRAUS GH;
Indirizzi:
UNIV GOTTINGEN,INST MIKROBIOL & GENET,GRISEBACHSTR 8 D-37077 GOTTINGEN GERMANY UNIV GOTTINGEN,INST MIKROBIOL & GENET D-37077 GOTTINGEN GERMANY HARVARD UNIV,GIBBS CHEM LAB CAMBRIDGE MA 02138
Titolo Testata:
Proceedings of the National Academy of Sciences of the United Statesof America
fascicolo: 6, volume: 95, anno: 1998,
pagine: 2868 - 2873
SICI:
0027-8424(1998)95:6<2868:SOIAAO>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
SACCHAROMYCES-CEREVISIAE; CRYSTAL-STRUCTURE; R-STATE; TRANSFORMATION; BIOSYNTHESIS; TRANSITION; TRYPTOPHAN; PATHWAY; RESIDUE; BINDING;
Keywords:
CLAISEN REARRANGEMENT; SITE-DIRECTED MUTAGENESIS; ALLOSTERIC REGULATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
25
Recensione:
Indirizzi per estratti:
Citazione:
G. Schnappauf et al., "SEPARATION OF INHIBITION AND ACTIVATION OF THE ALLOSTERIC YEAST CHORISMATE MUTASE", Proceedings of the National Academy of Sciences of the United Statesof America, 95(6), 1998, pp. 2868-2873

Abstract

Yeast chorismate mutase (EC 5.4.99.5) shows homotropic activation by the substrate, allosteric activation by tryptophan, and allosteric inhibition by tyrosine. In this study mutants of chorismate mutase have been found that remain sensitive to one allosteric effector (tryptophan) but insensitive to the other (tyrosine). These mutations are locatedin the catalytic domain: loop 220s (212-226) and helix 12 (227-251). The first example starts with the Thr-266 --> Ile mutant that had previously been shown to be locked in the activated R state. The additional mutation Ile-225 --> Thr unlocks the R state and restores the activation by tryptophan but not the inhibition by tyrosine. The second example refers to a molecular trigger for the switch between the T and R state: a hydrogen-bonded system, which stabilizes only the T state, from Tyr-234 to Glu-23 to Arg-157, Various mutants of Tyr-234, especiallyTyr-234 --> Phe, are unresponsive to tyrosine but are activated by tryptophan. This separation of activation from inhibition may indicate apathway for activation that is independent of the allosteric transition and may also be consistent with an intermediate structure between Tand R states.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/07/20 alle ore 23:45:15