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PDBsum entry 1kxx
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References listed in PDB file
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Key reference
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Title
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Analysis of the stabilization of hen lysozyme by helix macrodipole and charged side chain interaction.
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Authors
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H.Motoshima,
S.Mine,
K.Masumoto,
Y.Abe,
H.Iwashita,
Y.Hashimoto,
Y.Chijiiwa,
T.Ueda,
T.Imoto.
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Ref.
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J Biochem (tokyo), 1997,
121,
1076-1081.
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PubMed id
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Abstract
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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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