Molecular cloning of a cDNA encoding a soluble protein in the coral exoskeleton.
Organic substances were extracted from the calcified exoskeleton of the reef coral Galaxea fascicularis. In an SDS-PAGE analysis of the extract, a protein with an apparent molecular mass of 53 kDa was detected as well as two other weaker bands. A Ca2+ overlay analysis failed to find a Ca2+-binding protein in the extract. Periodic acid Schiff staining indicated that the 53 kDa protein was glycosylated. A cDNA containing the entire open reading frame for this protein was obtained. Analysis of the deduced protein sequence suggests that the protein, named galaxin, is synthesized as a precursor consisting of a signal peptide, a propeptide sequence, and a mature protein of 298 amino acids. Galaxin exhibits a novel amino acid sequence which is characterized by a tandem repeat structure. Galaxin transcripts were detected in the adult coral, but not in planktonic larvae.
Fukuda
Isao
I
Division of Marine Biosciences, Ocean Research Institute, The University of Tokyo, 1-15-1 Minamidai, Nakano, 168-8639, Tokyo, Japan.
Ooki
Syuuichi
S
Fujita
Toshihiro
T
Murayama
Emi
E
Nagasawa
Hiromichi
H
Isa
Yeishin
Y
Watanabe
Toshiki
T
D000595:Amino Acid Sequence; D037421:Anthozoa / Q000033:anatomy & histology / Q000378:metabolism / Q000502:physiology; D001483:Base Sequence; D002113:Calcification, Physiologic; D003001:Cloning, Molecular; D016384:Consensus Sequence; D018076:DNA, Complementary; D016326:Extracellular Matrix Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D020449:Repetitive Sequences, Amino Acid
D018076:DNA, Complementary; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins