title: The tertiary structure of an i-type lysozyme isolated from the common orient clam (Meretrix lusoria).
abstract: To evaluate the structure-function relationships of invertebrate lysozymes, a new invertebrate-type (i-type) lysozyme was isolated from the common orient clam (Meretrix lusoria) and the tertiary structure of this enzyme was determined. Comparison of the tertiary structure of this enzyme with those of chicken and Venerupi philippinarum lysozymes revealed that the location of the side chain of the second catalytic residue, an aspartic acid, and the N-acetylglucosamine trimer bound at subsites A-C were different. Furthermore, the amino acid electrostatically interacting with Asp30 in V. philippinarum lysozyme, Lys108, was substituted by Gly in M. lusoria lysozyme and no other possible amino acid that could contribute to this interaction was found in M. lusoria lysozyme. It therefore seems that the substitutions of the amino acids at the interface of the V. philippinarum lysozyme dimer are likely to change the oligomeric state of the M. lusoria lysozyme.
authors.affiliation: Department of Bioscience, School of Agriculture, Tokai University, Kawayo, Minamiaso, Kumamoto 869-1404, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kuwano
authors.forename: Kazunari
authors.initials: K
authors.lastname: Yoneda
authors.forename: Yuya
authors.initials: Y
authors.lastname: Kawaguchi
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Araki
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D049872:Bivalvia / Q000201:enzymology*; D002645:Chickens; D018360:Crystallography, X-Ray; D008969:Molecular Sequence Data; D009113:Muramidase / Q000737:chemistry* / Q000302:isolation & purification*; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
chemical_list: C421864:hen egg lysozyme; D009113:Muramidase
keywords: Meretrix lusoria; i-type lysozyme; invertebrates; tertiary structure