Publication Abstract from PubMed
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.
Analysis of the stabilization of hen lysozyme by helix macrodipole and charged side chain interaction.,Motoshima H, Mine S, Masumoto K, Abe Y, Iwashita H, Hashimoto Y, Chijiiwa Y, Ueda T, Imoto T J Biochem. 1997 Jun;121(6):1076-81. PMID:9354379[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
