Structural and biochemical characterization of a new type of lectin isolated from carp eggs.
A previously unidentified glycoprotein present in the eggs of the carp ( Cyprinus carpio ) was isolated and structurally characterized. The protein binds to a Sepharose 4B matrix and can be eluted with 0.4 M N -acetylglucosamine. The protein has an apparent molecular mass of 26686.3 Da. On the basis of gel-filtration chromatography, the protein appears to be present in solution as a monomer. The sequence of its 238 amino acids, the position of its four disulphide bridges and the composition of its single N-linked carbohydrate chain were determined. The lectin shows a very low agglutinating activity for human A-type erythrocytes and interacts with both Gram-positive and -negative bacteria. These latter interactions are inhibited by N -acetylglucosamine. A database search shows that its amino acid sequence is similar to that of the members of an invertebrate lectin family that includes tachylectin-1. Tachylectin-1 is present in the amoebocytes of the horseshoe crab, Tachypleus tridentatus, and plays a role in the innate defence system of this species. Homologous genes are also present in other fish, having 85% identity with a gene expressed in the oocytes of the crucian carp ( Carassius auratus gibelio ) and 78% identity with a gene in the cDNA library of the zebrafish ( Danio rerio ).
Galliano
Monica
M
Department of Biochemistry A. Castellani, University of Pavia, via Taramelli 3b, 27100 Pavia, Italy.
Minchiotti
Lorenzo
L
Campagnoli
Monica
M
Sala
Alberto
A
Visai
Livia
L
Amoresano
Angela
A
Pucci
Piero
P
Casbarra
Annarita
A
Cauci
Marco
M
Perduca
Massimiliano
M
Monaco
Hugo L
HL
D000595:Amino Acid Sequence; D000818:Animals; D001419:Bacteria / Q000378:metabolism; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000032:analysis; D002347:Carps / Q000235:genetics; D002850:Chromatography, Gel; D004220:Disulfides / Q000032:analysis; D005399:Fishes / Q000235:genetics; D007448:Invertebrates / Q000737:chemistry; D037102:Lectins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D010063:Ovum / Q000737:chemistry; D017386:Sequence Homology, Amino Acid
D002241:Carbohydrates; D004220:Disulfides; D037102:Lectins