Agarwalla S, Mellor I R, Sansom M S, Karle I L, Flippen-Anderson J L, Uma K, Krishna K, Sukumar M, Balaram P
Molecular Biophysics Unit, Indian Institute of Science, Bangalore.
Biochem Biophys Res Commun. 1992 Jul 15;186(1):8-15. doi: 10.1016/s0006-291x(05)80768-5.
Voltage dependent membrane channels are formed by the zervamicins, a group of alpha-aminoisobutyric acid containing peptides. The role of polar residues like Thr, Gln and Hyp in promoting helical bundle formation is established by dramatically reduced channel lifetimes for a synthetic apolar analog. Crystal structures of Leu1-zervamicin reveal association of bent helices. Polar contacts between convex faces result in an 'hour glass' like arrangement of an aqueous channel with a central constriction. The structure suggests that gating mechanisms may involve movement of the Gln11 carboxamide group. Gln3 may play a role in modulating the size of the channel mouth.
电压依赖性膜通道由zervamicins形成，zervamicins是一组含α-氨基异丁酸的肽。通过合成的非极性类似物显著缩短通道寿命，确定了苏氨酸、谷氨酰胺和羟脯氨酸等极性残基在促进螺旋束形成中的作用。Leu1-zervamicin的晶体结构揭示了弯曲螺旋的缔合。凸面之间的极性接触导致具有中央收缩的水通道呈“沙漏”状排列。该结构表明门控机制可能涉及Gln11羧酰胺基团的移动。Gln3可能在调节通道口大小方面发挥作用。
