The accessible surface of the nicotinic acetylcholine receptor. Identification by chemical modification and cross-linking with 14C-dimethyl suberimidate.
Eur J Biochem
; 252(2): 222-8, 1998 Mar 01.
Article
em En
| MEDLINE
| ID: mdl-9523692
ABSTRACT
To obtain structural information on the nicotinic acetylcholine receptor from Torpedo electric tissue we modified and cross-linked lysine residues with the agonistic bifunctional reagent [14C]dimethyl suberimidate. This reagent labels exposed lysine residues, especially those located near the ligand-binding site, and cross-links lysine residues located not more than 11 A, the length of the cross-linker, apart. Using this method, we identified a cross-link located between betaLys177 and betaLys191 showing that the 13 amino acids in between form a loop with these two residues located at the surface. Cross-linking also occurred between the vicinal lysine residues alphaLys76 and alphaLys77, indicating that these neighbouring lysine residues are not involved in a beta-sheet structure. A total of 21 out of 97 lysine residues present in the receptor were modified by [14C]dimethyl suberimidate. Thus these residues are located on the accessible extramembrane surface. The two lysine residues alphaLys76 and alphaLys179 were predominantly labelled. Because of the agonistic property of [14C]dimethyl suberimidate [Watty, A., Methfessel, C. & Hucho, F. (1997) Proc. Natl Acad. Sci. USA 94, 8202-8209] this might be due to their close proximity to the ligand binding site.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Receptores Nicotínicos
/
Dimetil Suberimidato
Tipo de estudo:
Diagnostic_studies
Limite:
Animals
Idioma:
En
Revista:
Eur J Biochem
Ano de publicação:
1998
Tipo de documento:
Article
País de afiliação:
Alemanha