Biochemical properties and cDNa cloning of two new lectins from the plasma of Tachypleus tridentatus -: Tachypleus plasma lectin 1 and 2+
Biochemical properties and cDNa cloning of two new lectins from the plasma of Tachypleus tridentatus -: Tachypleus plasma lectin 1 and 2+
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DOI：
10.1074/jbc.m008414200
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发表时间：
2001-03-30
影响因子：
4.8
通讯作者：
Liu, TY
中科院分区：
文献类型：
--
作者：
Chen, SC;Yen, CH;Liu, TY
从三齿鲎血浆中分离到一种Sepharose CL-4 B结合蛋白Tachypleus plasma lectin-1（TPL-1）和一种脂多糖（LPS）结合蛋白Tachypleus plasma lectin-2（TPL-2），并对其进行了生化鉴定。推导的TPL-1的氨基酸序列由232个氨基酸组成，在第74-76位残基处具有N-糖基化位点Asn-Gly-Ser。它与速凝素-1共享65%的序列同一性和约20个氨基酸基序的相似内部重复。TPL-8在含有0.4M GlcNAc和2 M KCl的缓冲液中从LPS-Sepbarose CL-4 B亲和柱上洗脱。TPL-2的推导氨基酸序列由128个氨基酸组成，在3-5位有一个N-糖基化位点Asn-Cys-Thr，TPL-2与从中国鲎变形细胞中分离的tachylectin-3有80%的同源性，通过LPS亲和柱从血浆中纯化的TPL-2主要以表观分子量为36 kDa的糖蛋白二聚体存在，速凝素-3是一种细胞内非糖基化蛋白，其在溶液中也以二聚体形式存在，表观分子量为29 kDa，它通过LPS的0-抗原识别革兰氏阴性菌，Western blot分析表明，在血浆中，TPL-1和TPL-2主要以分子量大于60 kDa的寡聚体存在，它们都与革兰氏阳性菌和革兰氏阴性菌结合，并且这种结合被GlcNAc抑制，TPL-1和TPL-8与细菌的可能结合位点可以在肽聚糖的GlcNAc-MurNAc的NAc部分处。TPL-1和TPL-2的生理功能最可能与它们形成互锁分子簇以捕获和诱捕入侵生物体的能力有关。
A Sepharose CL-4B-binding protein, Tachypleus plasma lectin 1 (TPL-1), and a lipopolysaccharide (LPS)binding protein, Tachypleus plasma lectin-2 (TPL-2), have been isolated from the plasma of Tachypleus tri-dentatus and biochemically characterized, Each protein is coded by a homologous family of multigenes, TPL-1 binds to Sepharose CL-4B and was eluted with buffer containing 0.4 M GlcNAc, The deduced amino acid sequence of TPL-1 consisted of 232 amino acids with an N-glycosylation site, Asn-Gly-Ser at residues 74-76. It shares a 65% sequence identity and similar internal repeats of about 20 amino acid motifs with tachylectin-1. Tachylectin-1 was identified as a lipopolysaccharideagarose binding nonglycosylated protein from the amebocytes of T, tridentatus, TPL-8 was eluted from the LPS-Sepbarose CL-4B affinity column in buffer containing 0.4 M GlcNAc and 2 M KCI, The deduced amino acid sequence of TPL-2 consisted of 128 amino acids with an N-glycosylation site, Asn-Cys-Thr, at positions 3-5, It shares an 80% sequence identity with tachylectin-3, isolated from the amebocytes of T, tridentatus, TPL-2 purified by LPS-affinity column from the plasma predominantly exists as a dimer of a glycoprotein with an apparent molecular mass of 36 kDa, Tachylectin-3 is an intracellular nonglycosylated protein that also exists as a dimer in solution with an apparent molecular mass of 29 kDa, It recognizes Gram-negative bacteria through the 0-antigen of LPS, Western blot analyses showed that, in the plasma, TPL-1 and TPL-2 exist predominantly as oligomers with molecular masses above 60 kDa, They both bind to Gram-positive and Gram-negative bacteria, and this binding is inhibited by GlcNAc, Possible binding site of TPL-1 and TPL-8 to the bacteria could be at the NAc moiety of GlcNAc-MurNAc of the peptidoglycan, The physiological function of TPL-1 and TPL-2 is most likely related to their ability to form a cluster of interlocking molecules to immobilize and entrap invading organisms.