Histidine-rich glycoprotein from the hemolymph of the marine mussel Mytilus edulis L. binds class A, class B, and borderline metals
Histidine-rich glycoprotein from the hemolymph of the marine mussel Mytilus edulis L. binds class A, class B, and borderline metals
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DOI：
10.1897/06-335r.1
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发表时间：
2007-05-01
影响因子：
4.1
通讯作者：
Robinson, William E.
中科院分区：
文献类型：
--
作者：
Devoid, Samantha J.;Etter, Ron;Robinson, William E.
很少有研究直接解决的问题，金属（必需的和非必需的）是如何在双壳类软体动物的循环系统中运输。富含组氨酸的糖蛋白（HRG）是一种潜在的金属转运蛋白，它是从贻贝（Mytilus edulis L.）的血浆中分离得到的。本研究进行了调查的程度贻贝HRG可以结合各种必需和非必需的金属在体外，使用固定化金属离子亲和层析（IMAC）和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳。平衡金属形态模型MINTEQA 2用于计算在充电和初始洗涤步骤期间结合至IMAC填充材料的金属的量。结果表明，HRG可以结合所有七种金属测试（钙，镉，汞，镁，镍，钯，锌）和HRG是唯一的金属结合蛋白在IMAC洗脱液。因为HRG-金属结合强度（log K-a）可能与组氨酸-金属结合强度相对应，并且因为HRG是主要的贻贝血浆蛋白，所以七种金属中的每一种的大部分可能作为蛋白结合金属而不是作为游离金属离子存在于贻贝血液中。发现一个单一的贻贝血浆蛋白可能是负责结合所有这些金属提出了重要的问题，这些不同的金属随后如何从HRG转移到不同的组织的贻贝，在那里他们可能会表现出组织特异性的模式的利用，螯合，消除和毒性。
Few studies have directly addressed the question of how metals (both essential and nonessential) are transported in the circulatory system of bivalve mollusks. One potential metal-transport protein, histidine-rich glycoprotein (HRG), has previously been isolated and characterized from the blood plasma of the marine mussel Mytilus edulis L. The present study was undertaken to investigate the extent to which mussel HRG can bind a variety of essential and nonessential metals in vitro, using immobilized metal-ion affinity chromatography (IMAC) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The equilibrium metal speciation model MINTEQA2 was used to compute the amount of metal that bound to the IMAC packing material during the charging and initial wash steps. Results demonstrated that HRG can bind all seven of the metals tested (Ca, Cd, Hg, Mg, Ni, Pd, and Zn) and that HRG is the only metal-binding protein in IMAC eluents. Because HRG-metal binding strengths (log K-a) likely correspond with histidine-metal binding strengths, and because HRG is the predominant mussel plasma protein, the majority of each of the seven metals probably would be present in mussel blood as protein-bound metal rather than as free metal ion. The finding that a single mussel plasma protein may be responsible for binding all these metals raises important questions about how these different metals are subsequently transferred from HRG to different tissues of the mussel, where they may exhibit tissue-specific patterns of utilization, sequestration, elimination, and toxicity.