Coombs R W, Verpoorte J A, Easterbrook K B
Biochim Biophys Acta. 1978 Aug 21;535(2):370-87. doi: 10.1016/0005-2795(78)90103-4.
Bacterial spinae from marine bacterium D71 are multi-subunit structures of a single protein. This protein, called spinin, is homogeneous by immunodiffusion and immunoelectrophoresis, amino acid composition, polyacrylamide gel electrophoresis with a number of buffer systems, sedimentation velocity and diffusion boundary analysis. Sedimentation equilibrium gives Mr = 19,000, while phosphate polyacryl-amide gel electrophoresis in presence of dodecyl sulfate gives Mr = 32,000. The lower Mr estimate for spinin is supported by sedimentation equilibrium in 6 M guanidine . HCl, and covalent cross-linking with dimethyl suberimidate or glutaraldehyde. The higher Mr value probably arises from an anomalous spinin-dodecyl sulfate interaction. Isoelectric focusing in polyacrylamide gel gives pI = 3.45; however, the focusing pattern also contains three distinct bands that may arise from hydrolysis of the spinin protomer during anodic migration. This study presents the first extensive physicochemical characterization of spinin and provides the basis for investigating the subunit assembly of spinae.
来自海洋细菌D71的细菌刺突是单一蛋白质的多亚基结构。这种蛋白质称为刺突蛋白，通过免疫扩散、免疫电泳、氨基酸组成、使用多种缓冲系统的聚丙烯酰胺凝胶电泳、沉降速度和扩散边界分析显示其具有均一性。沉降平衡给出的分子量为19,000，而在十二烷基硫酸钠存在下的磷酸聚丙烯酰胺凝胶电泳给出的分子量为32,000。在6M盐酸胍中的沉降平衡以及与辛二酸二甲酯或戊二醛的共价交联支持了刺突蛋白较低的分子量估计值。较高的分子量值可能源于刺突蛋白与十二烷基硫酸钠的异常相互作用。在聚丙烯酰胺凝胶中进行等电聚焦得到的等电点为3.45；然而，聚焦图谱中也包含三条不同的条带，这可能是由于刺突蛋白原体在阳极迁移过程中发生水解所致。本研究首次对刺突蛋白进行了广泛的物理化学表征，并为研究刺突的亚基组装提供了基础。
