Determination of the molecular dynamics of alamethicin using 13C NMR: implications for the mechanism of gating of a voltage-dependent channel.
Determination of the molecular dynamics of alamethicin using 13C NMR: implications for the mechanism of gating of a voltage-dependent channel.
复制标题
使用 13C NMR 测定阿拉甲辛的分子动力学：对电压依赖性通道门控机制的影响。
DOI：
10.1021/bi00137a007
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发表时间：
1992
期刊：
影响因子：
2.9
通讯作者：
Cafiso,DS
中科院分区：
文献类型：
--
作者：
Kelsh,LP;Ellena,JF;Cafiso,DS
弗吉尼亚大学化学与生物物理系，夏洛茨维尔，弗吉尼亚州 22901 收稿日期：1991 年 8 月 2 日；修订稿于 1991 年 12 月 30 日收到摘要：Alamethicin 是一种通道形成肽抗生素，可在平面双层中产生高度电压依赖性电导。为了深入了解其电压依赖性的机制，使用核磁共振检查了溶液中肽的动力学。在甲醇中的两种磁场强度下测量了阿拉甲辛的自然丰度 13C 自旋晶格弛豫率和 13C-'H 核奥弗豪瑟效应。使用无模型方法解释该信息，以获得总体相关时间以及肽内部运动的速率和幅度的值。阿拉甲辛的皮秒内部运动沿着肽主链受到高度限制，表明它在溶液中表现为刚性螺旋杆。随着距肽主链距离的增加，侧链碳表现出增加的链段运动；然而，这些动议并非不受限制。甲基动力学也与观察到的主链碳的受限运动一致。这些动力学测量没有证据表明肽关于脯氨酸 14 存在铰链运动。阿拉美星在甲醇中的结构似乎比在膜中的结构稍差；因此，阿拉甲星也有望在膜中表现为刚性螺旋。这表明该肽的门控涉及整个螺旋方向的变化，而不是肽主链片段的移动。膜蛋白中的电压依赖性构象转变对于许多过程至关重要，例如神经系统中的信息传递和能量。这项工作得到了美国国立卫生研究院 (GM-35215 to DSC) 的资助。转导。因此，即使在简单的模型系统中，这些机制的阐明也得到了积极的追求。 Alamethicin 是一种由 20 个氨基酸组成的小肽，当掺入平面双层或脂质囊泡时，会产生显着的电压依赖性电导。这种电压依赖性和阿拉甲辛的可拉伸尺寸使其成为一种有吸引力的药物。
Department of Chemistry and Biophysics Program, University of Virginia, Charlottesville, Virginia 22901 Received August 2, 1991; Revised Manuscript Received December 30, 1991 abstract: Alamethicin is a channel-forming peptide antibiotic that produces a highly voltage-dependent conductance in planar bilayers. To provide insightinto themechanisms for its voltagedependence, the dynamics of the peptide were examined in solution using nuclear magnetic resonance. Natural-abundance 13C spin-lattice relaxation rates and 13C-'H nuclear Overhauser effects of alamethicin were measured at two magneticfield strengths in methanol. This information was interpreted using a model-free approach to obtain values for the overall correlation times as well as the rates and amplitudes of the internal motions of the peptide. The picosecond, internal motions of alamethicin are highly restricted along the peptide backbone and indicatethat it behaves as a rigid helical rod in solution. The side chain carbons exhibit increased segmentalmotion as their distance from thepeptide backbone is increased; however, these motions are not unrestricted. Methyl group dynamics are also consistent with the restricted motions observed for the backbone carbons. There is no evidence from these dynamics measurements for a hinged motion of the peptide about proline-14. Alamethicin appears to be slightly less structured in methanol than in the membrane; as a result, alamethicin is also expected to behave as a rigid helix inthe membrane. This suggests that the gating of this peptide involves changes in the orientation of the entire helix, rather than the movement of a segment of the peptide backbone. voltage-dependent conformational transitions in membrane proteins are of central importance to many processes such as information transfer in the nervous system and energy fThis work was supported by a grant from the National Institutes of Health (GM-35215 to DSC). transduction. As a result, the elucidation of these mechanisms even in simple modelsystems has been actively pursued. Alamethicin is a small, 20 amino acid peptide that produces a dramatic voltage-dependentconductance when incorporated into planar bilayers or lipid vesicles. This voltagedependence and alamethicin’stractable size have made it an attractive