Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
THE N-GLYCOSIDASE MECHANISM OF RIBOSOME-INACTIVATING PROTEINS IMPLIEDBY CRYSTAL-STRUCTURES OF ALPHA-MOMORCHARIN
Autore:
REN JS; WANG YP; DONG YC; STUART DI;
Indirizzi:
OXFORD CTR MOLEC SCI,REX RICHARDS BLDG,S PARKS RD OXFORD OX1 3QU ENGLAND MOLEC BIOPHYS LAB OXFORD OX1 3QU ENGLAND ACAD SINICA,INST BIOPHYS BEIJING 100101 PEOPLES R CHINA
Titolo Testata:
Structure
fascicolo: 1, volume: 2, anno: 1994,
pagine: 7 - 16
SICI:
0969-2126(1994)2:1<7:TNMORP>2.0.ZU;2-T
Fonte:
ISI
Lingua:
ENG
Soggetto:
RICIN-A-CHAIN; SITE-DIRECTED MUTAGENESIS; EUKARYOTIC RIBOSOMES; ANTIVIRAL PROTEIN; ENZYMATIC INACTIVATION; GLUTAMIC ACID-177; ESCHERICHIA-COLI; AMP NUCLEOSIDASE; ACTIVE-SITE; RNA;
Keywords:
ALPHA-MOMORCHARIN; N-GLYCOSIDE BOND HYDROLYSIS; OXYCARBONIUM INTERMEDIATE; RIBOSOME-INACTIVATING PROTEIN;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
52
Recensione:
Indirizzi per estratti:
Citazione:
J.S. Ren et al., "THE N-GLYCOSIDASE MECHANISM OF RIBOSOME-INACTIVATING PROTEINS IMPLIEDBY CRYSTAL-STRUCTURES OF ALPHA-MOMORCHARIN", Structure, 2(1), 1994, pp. 7-16

Abstract

Background: alpha-Momorcharin (alpha MMC) is a type I ribosome-inactivating protein. It inhibits protein synthesis by hydrolytically removing a specific adenine residue from a highly conserved, single-strandedloop of rRNA. Results: Here we describe the determination and refinement of the crystal structures of alpha MMC in the native state and in complexes with the product, adenine, and a substrate analogue, formycin 5'-monophosphate (FMP) at high resolution. Both adenine and the baseof FMP are tightly bound; the ribose of bound FMP adopts a strained, high-energy conformation, which may mimic the structure of the transition state. Conclusions: These structures indicate that residues Tyr70,Glu160 and Arg163 of alpha MMC are the most critical for catalysis. We propose that the strained conformation of the ribose in the target adenosine weakens the glycoside bond. Partial protonation mediated by Arg163 then facilitates N-glycoside bond cleavage, leading to the formation of an oxycarbonium ion intermediate which is stabilized by the negatively-charged Glu160. Tyr70 adopts subtly different conformations in the three structures implying that it may be important in substrate recognition and perhaps catalysis.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 18/09/20 alle ore 17:02:49