Lijk L J, Kalk K H, Brandenburg N P, Hol W G
Biochemistry. 1983 Jun 7;22(12):2952-7. doi: 10.1021/bi00281a026.
Bovine liver rhodanese, which catalyzes the transfer of sulfur atoms between a variety of sulfur donor and sulfur acceptor substrates, is inhibited by metal cyanide complexes [Volini, M., Van Sweringen, B., & Chen, F.-Sh. (1978) Arch. Biochem. Biophys. 191, 205-215]. Crystallographic studies are described which reveal the binding mode of four different metal cyanides to bovine liver rhodanese: Na[Au(CN2], K2[Pt(CN)4], K2[Ni(CN)4], and K2[Zn(CN)4]. It appears that these complexes bind at one common site at the entrance of the active site pocket, interacting with the positively charged side chains of Arg-186 and Lys-249. This observation explains the inhibition of rhodanese by this class of compounds. For the platinum and nickel cyanide complexes virtually no other binding sites are observed. The gold complex binds, however, to three additional cysteine residues, thereby also displacing the extra sulfur atom which was bound to the essential Cys-247 in the sulfur-rhodanese complex. The zinc complex binds to completely different additional sites and forms complexes with the side chains of Asp-101 and His-203. Possible reasons for these different binding modes are discussed in terms of the preference for "hard" and "soft" ligands of these four metal ions.
牛肝硫氰酸酶可催化多种硫供体和硫受体底物之间硫原子的转移，它会受到金属氰化物络合物的抑制[沃利尼，M.，范·斯韦林根，B.，& 陈，F.-Sh.（1978年）《生物化学与生物物理学文献》191，205 - 215]。本文描述了晶体学研究，该研究揭示了四种不同金属氰化物与牛肝硫氰酸酶的结合模式：Na[Au(CN)₂]、K₂[Pt(CN)₄]、K₂[Ni(CN)₄]和K₂[Zn(CN)₄]。这些络合物似乎在活性位点口袋入口处的一个共同位点结合，与精氨酸 - 186和赖氨酸 - 249的带正电侧链相互作用。这一观察结果解释了这类化合物对硫氰酸酶的抑制作用。对于铂和镍的氰化物络合物，几乎未观察到其他结合位点。然而，金络合物还与另外三个半胱氨酸残基结合，从而也取代了与硫 - 硫氰酸酶络合物中必需的半胱氨酸 - 247结合的额外硫原子。锌络合物与完全不同的其他位点结合，并与天冬氨酸 - 101和组氨酸 - 203的侧链形成络合物。根据这四种金属离子对“硬”和“软”配体的偏好，讨论了这些不同结合模式的可能原因。
