Burkhart B M, Li N, Langs D A, Pangborn W A, Duax W L
Hauptman-Woodward Medical Research Institute, Inc., 73 High Street, Buffalo, NY 14203, USA.
Proc Natl Acad Sci U S A. 1998 Oct 27;95(22):12950-5. doi: 10.1073/pnas.95.22.12950.
The linear pentadecapeptide antibiotic, gramicidin D, is a naturally occurring product of Bacillus brevis known to form ion channels in synthetic and natural membranes. The x-ray crystal structures of the right-handed double-stranded double-helical dimers (DSDH) reported here agree with 15N-NMR and CD data on the functional gramicidin D channel in lipid bilayers. These structures demonstrate single-file ion transfer through the channels. The results also indicate that previous crystal structure reports of a left-handed double-stranded double-helical dimer in complex with Cs+ and K+ salts may be in error and that our evidence points to the DSDH as the major conformer responsible for ion transport in membranes.
线性十五肽抗生素短杆菌肽D是短芽孢杆菌的天然产物,已知其可在合成膜和天然膜中形成离子通道。本文报道的右手双链双螺旋二聚体(DSDH)的X射线晶体结构与脂质双层中功能性短杆菌肽D通道的15N-NMR和CD数据一致。这些结构表明离子通过通道单排传输。结果还表明,先前关于与Cs+和K+盐复合的左手双链双螺旋二聚体的晶体结构报告可能有误,我们的证据表明DSDH是负责膜中离子运输的主要构象体。