Zinc and mechanical prowess in the jaws of Nereis, a marine worm
Zinc and mechanical prowess in the jaws of Nereis, a marine worm
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DOI：
10.1073/pnas.1632658100
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发表时间：
2003-08-05
影响因子：
11.1
通讯作者：
Stucky, GD
中科院分区：
文献类型：
--
作者：
Lichtenegger, HC;Schöberl, T;Stucky, GD
高等动物通常依靠钙化来硬化某些组织，例如骨骼和牙齿。无脊椎动物中存在一些值得注意的例外：据报道，多种节肢动物的尖牙、牙齿和下颌骨都含有高含量的锌。海洋多毛类蠕虫沙蚕的颌部也含有大量的锌。最近，多毛类蠕虫 Glycera dibranchiata 中的高铜含量归因于铜基生物矿物质增强了颌骨。在本文中，我们尝试结合最先进的位置分辨技术来揭示锌在沙蚕下颌中的作用。结果表明，钳口的局部硬度和刚度与局部锌浓度相关，表明锌具有结构作用。检测到的锌总是与氯密切相关，表明存在锌氯化合物。然而，没有发现结晶无机相，并且X射线吸收光谱的结果进一步排除了无定形形式的简单无机锌-氯化合物的存在。蛋白质基质中局部组氨酸水平与锌浓度的相关性使我们推测锌和氯与蛋白质的直接配位。比较了过渡金属锌和铜分别在两种多毛类蠕虫沙蚕和 Glycera 的颌中的作用。
Higher animals typically rely on calcification to harden certain tissues such as bones and teeth. Some notable exceptions can be found in invertebrates: The fangs, teeth, and mandibles of diverse arthropod species have been reported to contain high levels of zinc. Considerable quantities of zinc also occur in the jaws of the marine polychaete worm Nereis sp. High copper levels in the polychaete worm Glycera dibranchiata recently were attributed to a copper-based biomineral reinforcing the jaws. In the present article, we attempt to unravel the role of zinc in Nereis limbata jaws, using a combination of position-resolved state-of-the-art techniques. It is shown that the local hardness and stiffness of the jaws correlate with the local zinc concentration, pointing toward a structural role for zinc. Zinc always is detected in tight correlation with chlorine, suggesting the presence of a zinc-chlorine compound. No crystalline inorganic phase was found, however, and results from x-ray absorption spectroscopy further exclude the presence of simple inorganic zinc-chlorine compounds in amorphous form. The correlation of local histidine levels in the protein matrix and zinc concentration leads us to hypothesize a direct coordination of zinc and chlorine to the protein. A comparison of the role of the transition metals zinc and copper in the jaws of two polychaete worm species Nereis and Glycera, respectively, is presented.