摘要
From the serum of Pangasianodon hypophthalmus, two proteins were isolated by affinity chromatography on Sepharose and phosphorylcholine–Sepharose. Their binding on the affinity matrices critically depends on the presence of Ca2+ ions. N-terminal sequencing and sequencing of internal tryptic peptides identified the proteins as pentraxins and from their binding properties they are identified as SAP (serum amyloid P component) and CRP (C-reactive protein). Per ml serum, 36 μg SAP and 56 μg CRP was purified. Upon gel filtration, both the SAP and CRP elute as trimers of respectively 24 kDa and 28 kDa subunits. Both proteins are devoid of inter-chain disulfide bonds. Both SAP and CRP are glycosylated and agglutinate rabbit erythrocytes and pathogenic bacteria Edwardsiella ictaluri and Aeromonas hydrophila, but not Micrococcus lysodeikticus or Escherichia coli. Haemagglutination of SAP and CRP is inhibited by galactose (MIC = 1 mM) and by phosphorylcholine (MIC = 1–2 mM), respectively. Circular dichroism studies revealed that antiparallel β-pleated sheets are dominating the secondary structure. Upon removing the Ca2+ ions by EDTA, slight structural changes are observed by CD spectroscopy in the near-UV region. Immunodiffusion shows that P. hypophthalmus SAP and CRP do not cross-react.
摘要译文
从Pangasianodon hypophthalmus的血清，两种蛋白质中分离由琼脂糖和磷酸胆碱琼脂糖亲和层析。其上的亲和基质结合的关键取决于钙SUP 2 / SUP离子的存在。和内部胰蛋白酶肽的测序鉴定的蛋白质为正五聚蛋白，并从它们的结合特性它们被标识为SAP（血清淀粉样蛋白P成分）和CRP（C反应蛋白）。每毫升血清，36两种蛋白都是缺乏链间二硫键。 SAP和CRP是糖基化和凝集兔红细胞和致病细菌爱德华ictaluri和嗜水气单胞菌，但不溶壁微球菌或大肠杆菌。 SAP和CRP的血凝是通过半乳糖（MIC \x3d 1毫米）和磷酰胆碱抑制（MIC \x3d 1-2毫米）中。圆二色谱研究表明，反平行轻微的结构变化是由光盘光谱在近紫外区观察到。免疫扩散表明P. hypophthalmus SAP和CRP的不发生交叉反应。
Duong Thi Huong Giang[a][b]; Edilbert Van Driessche[a]; Isabel Vandenberghe[c]; Bart Devreese[c]; Sonia Beeckmans[a]. Isolation and characterization of SAP and CRP, two pentraxins from Pangasianodon (Pangasius) hypophthalmus[J]. Fish & Shellfish Immunology, 2010,28(5-6): 743–753