A new lysozyme from the eastern oyster (Crassostrea virginica) indicates adaptive evolution of i-type lysozymes.
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.
Xue
Q-G
QG
Department of Veterinary Science, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
Itoh
N
N
Schey
K L
KL
Li
Y-L
YL
Cooper
R K
RK
La Peyre
J F
JF
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
D018076:DNA, Complementary; D009113:Muramidase