Transmembrane domain of cystic fibrosis transmembrane conductance regulator: design, characterization, and secondary structure of synthetic peptides m1-m6.
Transmembrane domain of cystic fibrosis transmembrane conductance regulator: design, characterization, and secondary structure of synthetic peptides m1-m6.
复制标题
囊性纤维化跨膜电导调节剂的跨膜结构域：合成肽 m1-m6 的设计、表征和二级结构。
DOI：
10.1021/bi972293n
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Thomas,PJ
中科院分区：
文献类型：
--
作者：
Wigley,WC;Vijayakumar,S;Jones,JD;Slaughter,C;Thomas,PJ
囊性纤维化跨膜传导调节因子(CFTR)的突变导致囊性纤维化(CF)，这是高加索人群中最常见的遗传病。CFTR被组织成五个假定的结构域，其中两个被预测为跨膜结构域，每个结构域由六个跨膜片段组成。CFTR介导调节阴离子跨上皮细胞顶膜的运输。CFTR运输其溶质的孔被认为是由氨基末端膜跨段的某种组合形成的。虽然预测这些序列在二级结构上是α-螺旋的，但到目前为止，还没有直接的结构证据来验证这一假说。在这里，我们介绍了六个肽(M1，−，M6)的生物物理特征，它们代表了预测的CFTR氨基端跨膜结构域。这些多肽可以被结合到脂质体中，并可溶于十二烷基硫酸钠胶束和三氟乙醇(TFE)。傅立叶变换红外光谱和圆二色谱表明，在这些环境中，所有六种多肽都采用了稳定的、以α-螺旋为主的二级结构。相反，多肽M6在20%甲醇中溶解时，经历了从α-螺旋到β-折叠的转变。此外，这些多肽显示，与在类自然环境中看到的相比，TFE中的β-Sheet增加，TFE是一种已知的α-螺旋的诱导剂。这些结果对这种复杂的膜蛋白的折叠有一定的意义，并表明M6可能的功能作用是通过二级结构的变化来体现的。
Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) give rise to cystic fibrosis (CF), the most common genetic disease in the Caucasian population. CFTR is organized into five putative domains, including two that are predicted to be transmembrane and consist of six membrane-spanning segments each. CFTR mediates regulated anion transport across the apical membrane of epithelial cells. The pore through which CFTR transports its solutes is thought to be formed by some combination of the amino-terminal membrane-spanning segments. Although these sequences are predicted to be α-helical in secondary structure, to date, no direct structural evidence has been presented testing this hypothesis. Here, we present the biophysical characterization of six peptides (m1−m6) representing the predicted amino-terminal membrane-spanning domain of CFTR. The peptides can be incorporated into liposomes and are soluble in SDS micelles and trifluoroethanol (TFE). FTIR and CD spectroscopy indicate all six peptides adopt a stable, predominantly α-helical secondary structure in these environments. In contrast, peptide m6 undergoes a shift from α-helix to β-sheet when dissolved in 20% methanol. Additionally, the peptides show an increase in β-sheet in TFE, a known inducer of α-helices, relative to that seen in the nativelike environments. These results have implications for the folding of this complex membrane protein and suggest that the possible functional role of m6 is manifested through a shift in secondary structure.