Universität Wien, Fakultät für Chemie, Institut für Biophysikalische Chemie, Althanstraße 14, 1090 Wien, Austria.
Chem Commun (Camb). 2019 Sep 24;55(77):11519-11522. doi: 10.1039/c9cc05818d.
The use of α- and β-Keggin polyoxotungstates (POTs) substituted by a single first row transition metal ion (CoII, NiII, CuII, ZnII) as superchaotropic crystallization additives led to covalent and non-covalent interactions with protein side-chains of proteinase K. Two major Keggin POT binding sites in proteinase K were identified, both stabilizing the orientation of the substituted metal site towards the protein surface and suggesting increased protein affinity for the substitution sites. The formation of all observed covalent bonds involves the same aspartate carboxylate, taking the role of a terminal oxygen with the Keggin α-isomer or even, in an unprecedented scenario, a bridging cluster oxygen with the β-isomer. Covalent bond formation with the protein carboxylate was observed only with the NiII- and CoII-substituted POTs, following the HSAB concept and the principle of metal immobilization.
使用由单个第一过渡金属离子（CoII、NiII、CuII、ZnII）取代的α-和β-Keggin 多金属氧酸盐（POTs）作为超离析结晶添加剂，导致与蛋白酶 K 的蛋白质侧链发生共价和非共价相互作用。鉴定出蛋白酶 K 中的两个主要的 Keggin POT 结合位点，都稳定了取代金属位点朝向蛋白质表面的方向，并表明对取代位点的蛋白质亲和力增加。所有观察到的共价键的形成都涉及相同的天冬氨酸羧酸盐，作为 Keggin α-异构体的末端氧，甚至在前所未有的情况下，作为β-异构体的桥接簇氧。只有 NiII 和 CoII 取代的 POT 与蛋白质的羧酸盐形成共价键，遵循 HSAB 概念和金属固定化原理。
