Analysis of the stabilization of hen lysozyme by helix macrodipole and charged side chain interaction.
J Biochem
; 121(6): 1076-81, 1997 Jun.
Article
en En
| MEDLINE
| ID: mdl-9354379
ABSTRACT
In the N-terminal region of the alpha-helix of the c-type lysozymes, two Asx residues exist at the 18th and 27th positions. Hen lysozyme has Asp18/Asn27 (18D/27N), and we prepared three mutant lysozymes, Asn18/Asn27 (18N/27N), Asn18/Asp27 (18N/27D), and Asp18/Asp27 (18D/27D). The stability of the wild-type (18D/27N) lysozyme supported the existence of a hydrogen bond between the side chain of Asp18 and the amide group at the N1 position in the alpha-helix, while the stability of the 18N/27D lysozyme supported the presence of the capping box between the Ser24 (N-cap) and Asp27 residues. Although electrostatic repulsion was observed between Asp18 and Asp27 residues in 18D/27D lysozyme, the dissociation of each residue contributed to stabilizing the B-helix in 18D/27D lysozyme through hydrogen bonding and charge-helix macrodipole interaction. This is the first evidence that two neighboring negative charges at the N-terminus of the helix both increased the stability of the protein.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Muramidasa
/
Estructura Secundaria de Proteína
Límite:
Animals
Idioma:
En
Revista:
J Biochem
Año:
1997
Tipo del documento:
Article