Bernués J, Espel E, Querol E
Biochim Biophys Acta. 1986 May 5;866(4):242-51. doi: 10.1016/0167-4781(86)90049-7.
High mobility group (HMG) nonhistone chromosomal proteins are a group of abundant, conservative and highly charged nuclear proteins whose physiological role in chromatin is still unknown. To gain insight into the interactions of HMG1 and HMG2 with the fundamental components of chromatin we have introduced the methodology of photochemical crosslinking. This technique has allowed us to study the interaction of HMG1 and HMG2 with the core histones, in the form of an H2A X H2B dimer and an (H3 X H4)2 tetramer, for an effective time of crosslinking of less than 1 ms and under very mild conditions. This is achieved by using flash photolysis. With this procedure we found that both HMG1 and HMG2 interact with H2A X H2B and also with (H3 X H4)2. In the second case, they seem to do this through histone H3. To obtain more information about the interactions, we split HMG1 and HMG2 into their peptides using staphylococcal proteinase. The peptides obtained, which reflect the domain distribution of these proteins, were then used along with the histone oligomers to elucidate their interactions by means of photochemical crosslinking. Results obtained indicate that the domain of HMG1 and HMG2 involved in the interaction with H2A X H2B histones is the highly acidic C-terminal, whereas the N-terminal is involved in the interactions with (H3 X H4)2 histones. In all cases, the interactions found appear appreciably strong. Along with other data published in the literature, these proteins appear to have at least one binding site per domain for the chromatin components.
高迁移率族（HMG）非组蛋白染色体蛋白是一类丰富、保守且带电量高的核蛋白，其在染色质中的生理作用尚不清楚。为了深入了解HMG1和HMG2与染色质基本成分的相互作用，我们引入了光化学交联方法。这项技术使我们能够在交联有效时间小于1毫秒且条件非常温和的情况下，研究HMG1和HMG2与以H2A×H2B二聚体和（H3×H4）2四聚体形式存在的核心组蛋白的相互作用。这是通过闪光光解实现的。通过这个过程，我们发现HMG1和HMG2都与H2A×H2B相互作用，也与（H3×H4）2相互作用。在第二种情况下，它们似乎是通过组蛋白H3来实现的。为了获得更多关于这些相互作用的信息，我们用葡萄球菌蛋白酶将HMG1和HMG2裂解成肽段。然后将得到的反映这些蛋白质结构域分布的肽段与组蛋白寡聚体一起用于通过光化学交联阐明它们的相互作用。所得结果表明，HMG1和HMG2中与H2A×H2B组蛋白相互作用的结构域是高度酸性的C末端，而N末端则参与与（H3×H4）2组蛋白的相互作用。在所有情况下，发现的相互作用都相当强。连同文献中发表的其他数据，这些蛋白质每个结构域似乎至少有一个与染色质成分结合的位点。
