Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Structure of the small G protein Rap2 in a non-catalytic complex with GTP
Autore:
Menetrey, J; Cherfils, J;
Indirizzi:
CNRS, Lab Enzymol & Biochim Struct, F-91198 Gif Sur Yvette, France CNRS Gif Sur Yvette France F-91198 truct, F-91198 Gif Sur Yvette, France
Titolo Testata:
PROTEINS-STRUCTURE FUNCTION AND GENETICS
fascicolo: 3, volume: 37, anno: 1999,
pagine: 465 - 473
SICI:
0887-3585(19991115)37:3<465:SOTSGP>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Soggetto:
GUANINE-NUCLEOTIDE-EXCHANGE; ACTIVATING PROTEIN; BIOCHEMICAL-CHARACTERIZATION; CRYSTAL-STRUCTURE; BINDING PROTEINS; EFFECTOR REGION; RAS PROTEIN; ACTIVE FORM; PRODUCT; GENE;
Keywords:
G protein; structure; GTPase; flexibility; Ras; disorder; hinge residue;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
55
Recensione:
Indirizzi per estratti:
Indirizzo: Cherfils, J CNRS, Lab Enzymol & Biochim Struct, F-91198 Gif Sur Yvette, France CNRS Gif Sur Yvette France F-91198 98 Gif Sur Yvette, France
Citazione:
J. Menetrey e J. Cherfils, "Structure of the small G protein Rap2 in a non-catalytic complex with GTP", PROTEINS, 37(3), 1999, pp. 465-473

Abstract

We report a novel crystal form of the small G protein Rap2A in complex with GTP which has no GTPase activity in the crystal. The asymmetric unit contains two complexes which show that a conserved switch I residue, Tyr 32, contributes an extra hydrogen bond to the gamma-phosphate of GTP as compared to related structures with GTP analogs. Since GTP is not hydrolyzed in the crystal, this interaction is unlikely to contribute to the intrinsic GTPaseactivity. The comparison of other G protein structures to the Rap2-GTP complex suggests that an equivalent interaction is likely to exist in their GTP form, whether unbound or bound to an effector. This interaction has to bereleased to allow the GAP-activated GTPase, and presumably the intrinsic GTPase activity as well. We also discuss the definition of the flexible regions and their hinges in the light of this structure and the expanding database of G protein structures. We propose that the switch I and switch II undergo either partial or complete disorder-to-order transitions according to their cellular status, thus defining a complex energy landscape comprising more than two conformational states. We observe in addition that the regionconnecting the switch I and switch II is flexible in Rapa and other G proteins. This region may be important for protein-protein interactions and possibly behave as a conformational lever arm, as characterized for Arf. Takentogether, these observations suggest that the structural mechanisms of small G proteins are significantly driven by entropy-based free energy changes. Proteins 1999;37:465-473. (C) 1999 Wiley-Liss, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/07/20 alle ore 17:22:04