Hitchings Matthew D, Townsend Philip, Pohl Ehmke, Facey Paul D, Jones D Hugh, Dyson Paul J, Del Sol Ricardo
College of Medicine, Swansea University, Singleton Park, Swansea, SA2 8PP, UK.
Cell Mol Life Sci. 2014 Dec;71(24):4911-26. doi: 10.1007/s00018-014-1658-4. Epub 2014 Jun 11.
Dps proteins are members of an extensive family of proteins that oxidise and deposit iron in the form of ferric oxide, and are also able to bind DNA. Ferroxidation centres are formed at the interface of anti-parallel dimers, which further assemble into dodecameric nanocages with a hollow core where ferric oxide is deposited. Streptomyces coelicolor encodes three Dps-like proteins (DpsA, B and C). Despite sharing the conserved four-helix bundle organisation observed in members of the Dps family, they display significant differences in the length of terminal extensions, or tails. DpsA possess both N- and C-terminal tails of different lengths, and their removal affects quaternary structure assembly to varying degrees. DpsC quaternary structure, on the other hand, is heavily dependent on its N-terminal tail as its removal abolishes correct protein folding. Analysis of the crystal structure of dodecamers from both proteins revealed remarkable differences in the position of tails and interface surface area; and provides insight to explain the differences in biochemical behaviour observed while comparing DpsA and DpsC.
Dps蛋白是一个庞大蛋白质家族的成员，该家族能将铁氧化并以氧化铁的形式沉积，同时还能结合DNA。铁氧化中心在反平行二聚体的界面处形成，这些二聚体进一步组装成具有中空核心的十二聚体纳米笼，氧化铁就沉积在这个中空核心中。天蓝色链霉菌编码三种类Dps蛋白（DpsA、B和C）。尽管它们具有在Dps家族成员中观察到的保守的四螺旋束结构，但它们在末端延伸部分（即尾巴）的长度上存在显著差异。DpsA具有不同长度的N端和C端尾巴，去除它们会对四级结构组装产生不同程度的影响。另一方面，DpsC的四级结构严重依赖其N端尾巴，因为去除该尾巴会破坏蛋白质的正确折叠。对这两种蛋白质的十二聚体晶体结构分析揭示了尾巴位置和界面表面积的显著差异；并为解释在比较DpsA和DpsC时观察到的生化行为差异提供了见解。
