Department of Life and Environmental Sciences, Laboratory of Photobiology and Plant Physiology, University of Cagliari, V.le S. Ingnazio da Laconi 13, 09123 Cagliari, Italy; Department of Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 52175 Bonn, Germany.
Department of Life and Environmental Sciences, Laboratory of Molecular Virology, University of Cagliari, Cittadella Universitaria di Monserrato, SS554, 09042 Monserrato, Cagliari, Italy.
Food Res Int. 2017 Sep;99(Pt 2):868-876. doi: 10.1016/j.foodres.2016.10.003. Epub 2016 Oct 11.
S-layers are regular paracrystalline arrays of proteins or glycoproteins that characterize the outer envelope of several bacteria and archaea. The auto-assembling properties of these proteins make them suitable for application in nanotechnologies. However, the bacterial cell wall and its S-layer are also an important binding sites for carotenoids and they may represent a potential source of these precious molecules for industrial purposes. The S-layer structure and its components were extensively studied in the radio-resistant bacterium Deinococcus radiodurans, which for long time represented one of the model organisms in this respect. The protein DR_2577 has been shown to be one of the naturally over-expressed S-layer components in this bacterium. The present report describes a high scale purification procedure of this protein in solution. The purity of the samples, assayed by native and denaturing electrophoresis, showed how this method leads to a selective and high efficient recovery of the pure DR_2577. Recently, we have found that the deinoxanthin, a carotenoid typical of D. radiodurans, is a cofactor non covalently bound to the protein DR_2577. The pure DR_2577 samples may be precipitated or lyophilized and used as a source of the carotenoid cofactor deinoxanthin by an efficient extraction using organic solvents. The procedure described in this work may represent a general approach for the isolation of S-layer proteins and their carotenoids with potentials for industrial applications.
S-层是由蛋白质或糖蛋白组成的规则的准晶阵列，其特征在于几种细菌和古菌的外包膜。这些蛋白质的自动组装特性使它们适合应用于纳米技术。然而，细菌细胞壁及其 S-层也是类胡萝卜素的重要结合部位，它们可能代表了这些珍贵分子的潜在工业来源。在抗辐射细菌 Deinococcus radiodurans 中，对 S-层结构及其成分进行了广泛研究，该细菌长期以来一直是这方面的模式生物之一。已经表明，蛋白质 DR_2577 是该细菌中天然过表达的 S-层成分之一。本报告描述了该蛋白质在溶液中的大规模纯化程序。通过天然和变性电泳测定的样品纯度表明，该方法如何导致对纯 DR_2577 的选择性和高效回收。最近，我们发现，脱氮叶黄素，一种典型的 D. radiodurans 类胡萝卜素，是非共价结合到蛋白质 DR_2577 上的辅因子。通过使用有机溶剂进行有效的提取，可以将纯 DR_2577 样品沉淀或冻干，并用作类胡萝卜素辅因子脱氮叶黄素的来源。本工作中描述的程序可能代表了一种用于分离 S-层蛋白及其类胡萝卜素的通用方法，具有潜在的工业应用价值。
