The major soluble 19.6 kDa protein of the organic shell matrix of the freshwater snail Biomphalaria glabrata is an N-glycosylated dermatopontin.
The major Biomphalaria glabrata shell matrix protein of 19.6 kDa was isolated by preparative electrophoresis and sequenced. The sequence of 148 amino acids showed 32% sequence identity to mammalian dermatopontin sequences and 34-37% identity to two invertebrate dermatopontins described previously. A unique feature of the shell matrix dermatopontin was the presence of a single N-glycosylation consensus sequence, the asparagine of which was completely modified with a pentasaccharide. Sequence analysis of this short N-glycan by mass spectrometry and carbohydrate composition analysis indicated that it was the ubiquitous N-glycan core oligosaccharide with the exception that the terminal mannoses were 3-O-methylated. Dermatopontin is widespread in mammalian extracellular matrices, including the matrix of biominerals such as bone and teeth. Its occurrence in an invertebrate biomineral indicates that such phylogenetically distant biomineral-forming systems as vertebrate bone and mollusk shell share components which have undergone surprisingly few changes during a long evolution.
Marxen
Julia C
JC
Zoologisches Institut und Museum der Universität Hamburg, D-20146 Hamburg, Germany.
Nimtz
Manfred
M
Becker
Wilhelm
W
Mann
Karlheinz
K
D000595:Amino Acid Sequence; D000818:Animals; D001700:Biomphalaria / Q000378:metabolism*; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000302:isolation & purification / Q000378:metabolism*; D011508:Chondroitin Sulfate Proteoglycans; D004591:Electrophoresis, Polyacrylamide Gel; D016326:Extracellular Matrix Proteins; D006031:Glycosylation; D006801:Humans; D008969:Molecular Sequence Data
D002352:Carrier Proteins; D015815:Cell Adhesion Molecules; D011508:Chondroitin Sulfate Proteoglycans; C082019:DPT protein, human; D016326:Extracellular Matrix Proteins