Purification and characterisation of a natural lectin from the serum of the shrimp Litopenaeus vannamei.
A natural lectin from the serum of the shrimp Litopenaeus vannamei was purified to homogeneity by a single-step affinity chromatography using fetuin-coupled agarose. The purified serum lectin (named LVL) showed a strong affinity for human A/B/O erythrocytes (RBC), mouse RBC, chicken RBC and its haemagglutinating (HA) activity was specifically dependent on Ca2+ and reversibly sensitive to EDTA. LVL inactive form had a molecular mass estimate of 172 kDa and was composed of two non-identical subunits (32 and 38 kDa) cross-linked by interchain disulphide bonds. Significant LVL activity was observed between pH 7 and 11. In HA-inhibition assays performed with several carbohydrates and glycoproteins, LVL showed a distinct and unique specificity for GalNAc/GluNAc/NeuAc which had an acetyl group, while glycoproteins fetuin and bovine submaxillary mucin (BSM) had sialic acid. Moreover, this agglutinin appeared to recognise the terminal N- and O-acetyl groups in the oligosaccharide chain of glycoconjugates. The HA activity of L. vannamei lectin was also susceptible to inhibition by lipopolysaccharides from diverse Gram-negative bacteria, which might indicate a significant in vivo role of this humoral agglutinin in the host immune response against bacterial infections.
Sun
Jie
J
Institute of Oceanology, The Chinese Academy of Sciences, Qingdao 266071, Shandong, PR China.
Wang
Lei
L
Wang
Baojie
B
Guo
Zhenyu
Z
Liu
Mei
M
Jiang
Keyong
K
Luo
Zuoyong
Z
D000818:Animals; D002645:Chickens; D020609:Edwardsiella tarda / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000737:chemistry / Q000276:immunology; D006385:Hemagglutination Inhibition Tests; D006458:Hemolymph / Q000737:chemistry / Q000276:immunology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D037102:Lectins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification*; D051379:Mice; D008856:Microscopy, Fluorescence; D008970:Molecular Weight; D033561:Penaeidae / Q000737:chemistry* / Q000276:immunology; D013291:Streptococcus / Q000276:immunology; D013696:Temperature; D014733:Vibrio / Q000276:immunology
D037102:Lectins