Importance of indole N-H hydrogen bonding in the organization and dynamics of gramicidin channels.
Importance of indole N-H hydrogen bonding in the organization and dynamics of gramicidin channels.
复制标题
DOI：
10.1016/j.bbamem.2013.10.011
复制
发表时间：
2014-01
影响因子：
3.4
通讯作者：
Chattopadhyay, Amitabha
中科院分区：
文献类型：
--
作者：
Chaudhuri, Arunima;Haldar, Sourav;Sun, Haiyan;Koeppe, Roger E., II;Chattopadhyay, Amitabha
线性离子通道肽短杆菌肽代表了探索膜蛋白结构和功能的基本原理，特别是关于色氨酸残基的一个很好的模型。短杆菌肽通道中的色氨酸残基对通道的结构和功能至关重要。为了测试吲哚氢键的短杆菌肽通道的生物物理性质的重要性，我们监测短杆菌肽的N-甲基化的影响，使用稳态和时间分辨荧光方法的组合沿着圆二色光谱。我们在这里表明，在没有氢键的能力，四甲基色氨酸短杆菌肽（TM-短杆菌肽）是无法维持单链，头对头二聚体通道构象的膜。我们的研究结果表明，TM-短杆菌肽显示红移的荧光发射最大值，较低的红边激发位移（REES），更高的荧光强度和寿命，符合其非通道构象。这与使用视差法测量的TM-短杆菌肽中1-甲基双氢吡喃的位置（平均深度）一致。这些结果显示了1-甲基色氨酸作为荧光工具来检测蛋白质和肽中色氨酸的氢键结合能力的有用性。我们的结论是，随着肽骨架结构的变化，沿着单链β6.3螺旋二聚体构象的丧失，单链β6.3螺旋二聚体的氢键能力发生了变化。这些结果同意早期的结果从尺寸排阻色谱和单通道测量TM-短杆菌肽，并确认吲哚氢键的重要性的构象和功能的离子通道和膜蛋白。
The linear ion channel peptide gramicidin represents an excellent model for exploring the principles underlying membrane protein structure and function, especially with respect to tryptophan residues. The tryptophan residues in gramicidin channels are crucial for the structure and function of the channel. In order to test the importance of indole hydrogen bonding for the biophysical properties of gramicidin channels, we monitored the effect of N-methylation of gramicidin tryptophans, using a combination of steady state and time-resolved fluorescence approaches along with circular dichroism spectroscopy. We show here that in the absence of hydrogen bonding ability of tryptophans, tetramethyltryptophan gramicidin (TM-gramicidin) is unable to maintain the single stranded, head-to-head dimeric channel conformation in membranes. Our results show that TM-gramicidin displays a red-shifted fluorescence emission maximum, lower red edge excitation shift (REES), and higher fluorescence intensity and lifetime, consistent with its nonchannel conformation. This is in agreement with the measured location (average depth) of the 1-methyltryptophans in TM-gramicidin using the parallax method. These results bring out the usefulness of 1-methyltryptophan as a fluorescent tool to examine the hydrogen bonding ability of tryptophans in proteins and peptides. We conclude that changes in the hydrogen bonding ability of tryptophans, along with coupled changes in peptide backbone structure induce the loss of single stranded β6.3 helical dimer conformation. These results agree with earlier results from size-exclusion chromatography and single-channel measurements for TM-gramicidin, and confirm the importance of indole hydrogen bonding for the conformation and function of ion channels and membrane proteins.
登录
查看更多内容
DOI：
10.1080/01483918408067046
发表时间：
1984-01-01
期刊：
JOURNAL OF LIQUID CHROMATOGRAPHY
影响因子：
--
作者：
BARON, CB;COBURN, RF
通讯作者：
COBURN, RF
影响因子：
3.4
作者：
Chattopadhyay, Amitabha;Rawat, Satinder S.;Koeppe, Roger E., II
通讯作者：
Koeppe, Roger E., II
影响因子：
2.9
作者：
CHATTOPADHYAY, A;LONDON, E
通讯作者：
LONDON, E
DOI：
10.1016/0005-2736(91)90249-8
发表时间：
1991-07-01
期刊：
BIOCHIMICA ET BIOPHYSICA ACTA
影响因子：
--
作者：
BARTH, C;STARK, G
通讯作者：
STARK, G
影响因子：
3.4
作者：
Chattopadhyay, A;Mukherjee, S;Sudha, S
通讯作者：
Sudha, S