title: A new lysozyme from the eastern oyster (Crassostrea virginica) indicates adaptive evolution of i-type lysozymes.
abstract: A new lysozyme (cv-lysozyme 2) with a MALDI molecular mass of 12 984.6 Da was purified from crystalline styles and digestive glands of eastern oysters (Crassostrea virginica) and its cDNA sequenced. Quantitative real time RT-PCR detected cv-lysozyme 2 gene expression primarily in digestive gland tissues, and in situ hybridization located cv-lysozyme 2 gene expression in basophil cells of digestive tubules. Cv-lysozyme 2 showed high amino acid sequence similarity to other bivalve mollusk lysozymes, including cv-lysozyme 1, a lysozyme recently purified from C. virginica plasma. Differences between cv-lysozyme 2 and cv-lysozyme 1 molecular characteristics, enzymatic properties, antibacterial activities, distribution in the oyster body and site of gene expression indicate that the main role of cv-lysozyme 2 is in digestion. While showing that a bivalve mollusk employs different lysozymes for different functions, findings in this study suggest adaptive evolution of i type lysozymes for nutrition.
authors.affiliation: Department of Veterinary Science, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
authors.forename: Q-G
authors.initials: QG
authors.lastname: Xue
authors.forename: N
authors.initials: N
authors.lastname: Itoh
authors.forename: K L
authors.initials: KL
authors.lastname: Schey
authors.forename: Y-L
authors.initials: YL
authors.lastname: Li
authors.forename: R K
authors.initials: RK
authors.lastname: Cooper
authors.forename: J F
authors.initials: JF
authors.lastname: La Peyre
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D049896:Crassostrea / Q000201:enzymology* / Q000378:metabolism; D018076:DNA, Complementary; D019143:Evolution, Molecular; D015971:Gene Expression Regulation, Enzymologic; D008969:Molecular Sequence Data; D009113:Muramidase / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D010802:Phylogeny; D016415:Sequence Alignment
chemical_list: D018076:DNA, Complementary; D009113:Muramidase