Stone K J, Strominger J L
Proc Natl Acad Sci U S A. 1971 Dec;68(12):3223-7. doi: 10.1073/pnas.68.12.3223.
The inhibition by bacitracin of the enzymatic dephosphorylation of C(55)-isoprenyl pyrophosphate is abolished by the addition of chelating agents. If, however, the chelating agent is added after a preincubation of bacitracin with a divalent cation and the lipid substrate, then its addition has little effect, indicating that bacitracin, metal ion, and C(55)-isoprenyl pyrophosphate form a complex. Various divalent cations can participate in complex formation, but monovalent cations are ineffective. A direct demonstration of the formation of a complex between the C(55)-isoprenyl pyrophosphate and bacitracin in the presence of metal ions was obtained. Molecular models that show one possible conformation for a complex between bacitracin and the C(55)-isoprenyl pyrophosphate, in which the metal ion acts as a bridge between the two compounds, are presented.
加入螯合剂后，杆菌肽对C（55）-异戊烯基焦磷酸酶促去磷酸化的抑制作用被消除。然而，如果在杆菌肽与二价阳离子和脂质底物预孵育后加入螯合剂，那么其加入几乎没有效果，这表明杆菌肽、金属离子和C（55）-异戊烯基焦磷酸形成了一种复合物。各种二价阳离子都可以参与复合物的形成，但一价阳离子无效。直接证明了在金属离子存在下C（55）-异戊烯基焦磷酸与杆菌肽之间形成了复合物。文中给出了分子模型，展示了杆菌肽与C（55）-异戊烯基焦磷酸之间复合物的一种可能构象，其中金属离子作为两种化合物之间的桥梁。
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