Prediction of a conserved, neutralizing epitope in ribosome-inactivating proteins.
Int J Biol Macromol
; 24(1): 19-26, 1999 Jan.
Article
en En
| MEDLINE
| ID: mdl-10077268
The secondary structures, side-chain solvent accessibilities, and superpositioned crystal structures of the A-chain of ricin and four other plant rRNA N-glycosidases (ribosome-inactivating proteins, RIPs) were examined. Previously, a 26-residue fragment from the A-chain of ricin was determined to bind to a neutralizing monoclonal antibody. The region in the native ricin A-chain, to which this peptide corresponds, is solvent-exposed and contains a negatively charged residue that has been hypothesized to participate in the toxin's function, namely, rRNA binding and/or enzymatic activity. This region appears to be conserved in all of the structurally defined plant RIPs examined. Moreover, other plant RIPs, whose tertiary structures are, as yet, unknown, were predicted to have an analogous, solvent-exposed region containing a conserved, negatively charged residue. By analogy, these conserved structural and functional features lead to the suggestion that this exposed region represents a logical starting point for experiments designed to locate neutralizing epitopes in these RIPs. In contrast, the tertiary structure of the analogous region in a bacteria-derived RIP (Shiga toxin) is a less solvent-exposed, truncated loop and is a structure that is not as likely to be a neutralizing epitope. Because most of the amino acid residues are not conserved within this exposed region, these RIPs are predicted to be antigenically distinct.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteínas Ribosómicas
/
Ricina
/
Epítopos
/
N-Glicosil Hidrolasas
Tipo de estudio:
Prognostic_studies
/
Risk_factors_studies
Idioma:
En
Revista:
Int J Biol Macromol
Año:
1999
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Países Bajos