Agbaje Oluwatoosin B A, Dominguez J Gabriel, Jacob Dorrit E
Department of Earth and Environmental Sciences, Macquarie University, Sydney, Australia.
Department of Biological Sciences, Macquarie University, Sydney, Australia.
Biochem Biophys Rep. 2021 Feb 12;26:100939. doi: 10.1016/j.bbrep.2021.100939. eCollection 2021 Jul.
Biochemical studies and spectroscopic techniques have shown that chitin-silk fibroins are common in nacroprismatic bivalve shells. However, the nature of organic biopolymers in the less well studied shell architectures, such as crossed lamellar shells, remain unknown. Here, two venus shells, and , with crossed lamellar ultrastructure have been studied.
We employed thermal gravimetric analysis, optical-, confocal- and scanning electron-microscopes, gel-sodium dodecyl sulfate (gel-SDS), FTIR, ultra-performance liquid chromatography and high-performance anion-exchange chromatography system with pulsed amperometric detection to analyse organic macromolecules in shells.
Thermal analysis showed a low concentration of organic macromolecules in (1.38 wt%) and in (1.71 wt%). A combination of biochemical protocols, including Calcofluor White staining and FTIR spectroscopic assessment, indicate that amino-polysaccharide chitin together with proteins, are present in the organic scaffolding of shells. Scanning electron microscope of insoluble acid biopolymer extracts as well as FTIR technique show that the hierarchical structural organizations of organic biopolymers consist collagen-related matrix. Our histochemical fixing and staining techniques reveal many discrete proteins and glycoproteins from soluble organic macromolecules on the gel-SDS. We show here 'singlet' and 'doublet' glycosaminoglycan bands that are far above 260 kDa.
GENERAL SIGNIFICANCE/CONCLUSIONS: The presence of collagen matrix in shells shows promise for the new source of biomaterials. Most importantly, the structural organization of the proteinaceous motif is predominantly helical structures and not silk-fibroin unlike in nacreous bivalve shells.
生物化学研究和光谱技术表明，几丁质 - 丝素蛋白在珍珠质双壳贝类贝壳中很常见。然而，在研究较少的贝壳结构中，如交叉层状贝壳，有机生物聚合物的性质仍然未知。在这里，我们研究了两个具有交叉层状超微结构的维纳斯贝壳， 和 。
我们采用热重分析、光学显微镜、共聚焦显微镜和扫描电子显微镜、凝胶 - 十二烷基硫酸钠（凝胶 - SDS）、傅里叶变换红外光谱（FTIR）、超高效液相色谱和带脉冲安培检测的高效阴离子交换色谱系统来分析 贝壳中的有机大分子。
热分析表明， 在 中的有机大分子浓度较低（1.38 wt%），在 中为（1.71 wt%）。包括荧光增白剂染色和FTIR光谱评估在内的一系列生化方法表明，氨基多糖几丁质与蛋白质一起存在于 贝壳的有机支架中。不溶性酸性生物聚合物提取物的扫描电子显微镜以及FTIR技术表明，有机生物聚合物的层次结构组织由胶原蛋白相关基质组成。我们的组织化学固定和染色技术揭示了凝胶 - SDS上可溶性有机大分子中的许多离散蛋白质和糖蛋白。我们在这里展示了远高于260 kDa的“单峰”和“双峰”糖胺聚糖带。
一般意义/结论： 贝壳中胶原蛋白基质的存在为生物材料的新来源带来了希望。最重要的是，与珍珠质双壳贝类贝壳不同，蛋白质基序的结构组织主要是螺旋结构，而不是丝素蛋白。
