Identification of the receptor-recognition surface of bombyxin-II, an insulin-like peptide of the silkmoth Bombyx mori: critical importance of the B-chain central part.
J Mol Biol
; 253(5): 759-70, 1995 Nov 10.
Article
em En
| MEDLINE
| ID: mdl-7473750
ABSTRACT
Bombyxin-II, a brain-secretory peptide of the silkmoth Bombyx mori, shares 40% sequence identify and the characteristics core structure with human insulin. In spite of the structural similarity, no cross-activity is observed between them. To localize the active region of bombyxin-II, we have synthesized chimeric molecules of bombyxin-II and human insulin, and examined their bombyxin activity. Two chimeric molecules, which were sequentially identical except for the B-chain central part, showed significantly different potencies in bombyxin activity. Solution structure determination of these chimeric molecules revealed that their B-chain central parts took similar main-chain conformation, but formed dissimilar patches on their molecular surfaces. Therefore, the surface patch formed by the central part of the bombyxin-II B-chain is of critical importance for recognition of the bombyxin receptor. The above results, together with other data on the structure-activity relationships of bombyxin, indicate that the receptor-recognition surface of bombyxin-II includes the A-chain N and C, termini in addition to the B-chain central part. Though bombyxin-II, human insulin and human relaxin 2 use the common surface as their receptor-recognition sites, each of the surface patches is characterized by the variety of involved side-chains. Insulin and relaxin involve additional parts for receptor recognition, particularly the B-chain C-terminal part and the extended A-chain N-terminal helix, respectively. In conclusion, these ligands have evolved their own specific mechanisms for receptor recognition while retaining the major recognition surface.
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Bases de dados:
MEDLINE
Assunto principal:
Conformação Proteica
/
Bombyx
/
Neuropeptídeos
/
Receptores de Superfície Celular
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Animals
/
Humans
Idioma:
En
Revista:
J Mol Biol
Ano de publicação:
1995
Tipo de documento:
Article
País de afiliação:
Japão