STRUCTURAL CHARACTERISTICS OF ALPHA-HELICAL PEPTIDE MOLECULES CONTAINING AIB RESIDUES
STRUCTURAL CHARACTERISTICS OF ALPHA-HELICAL PEPTIDE MOLECULES CONTAINING AIB RESIDUES
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DOI：
10.1021/bi00481a001
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发表时间：
1990-07-24
期刊：
影响因子：
2.9
通讯作者：
BALARAM, P
中科院分区：
文献类型：
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作者：
KARLE, IL;BALARAM, P
氨基异丁酰残基-NHC (CH3) 2C (0)-(Aib或U)虽然不是蛋白质中发现的20个氨基酸残基之一，但却是微生物来源产生的肽中常见的残基。具有抗生素特性的此类肽的例子是衣霉素，一种具有环状主链的肽（Closse & Huguenin，1974；Flippen & Karle，1976），以及由 15-20 个残基组成的线性肽，例如丙氨酸-甲氧西林（ala-methicin）、抗阿米宾（antiamoebin）、艾美米星（emerimicin）和泽瓦霉素（zervamicin）（Rinehart 等，1979），它们产生 脂质膜中的电压门控离子通道（Mueller & Rudin，1968；Mathew & Balaram，1983）。除了蛋白质中存在的 L 残基外，每个线性肽还包含 5-8 个 Aib 残基。阿拉甲星晶体结构的初步结果（Fox & Richards，1982）表明，20 个残基的阿拉甲星分子折叠成主要为 a 螺旋的单螺旋。最近，一篇发表的关于三氯嗪晶体结构的摘要（Le Bars et al., 1988）报道称其构象与阿拉甲辛非常相似。用另一个甲基取代丙氨酸残基中 C“原子上的质子严重限制了 NC” 和 C“-C' 键可能的旋转。这些键的扭转角分别由 和 指定。以 Ramachandran 等人（1963，1968）的方式计算允许和空间，Marshall 和 Bosshard（1972）以及 Burgess 和 Leach (1973) 表明，Aib 残基的允许角度和角度发生在靠近 57、-47 和 + 57、+ 47 的两个非常有限的区域中。
The-aminoisobutyryl residue-NHC (CH3) 2C (0)-(Aib or U), although not one of the 20 amino acid residues found in proteins, is a common residue that occurs in peptides produced by microbial sources. Examples of such peptides that possess antibiotic properties are chlamydocin, a peptide with a cyclic backbone (Closse & Huguenin, 1974; Flippen & Karle, 1976), and linear peptidescomposed of 15-20 residues such as ala-methicin, antiamoebin, emerimicin, and zervamicin (Rinehart et al., 1979) that produce voltage-gated ion channels in lipid membranes (Mueller & Rudin, 1968; Mathew & Balaram, 1983). Each of the linear peptides contains 5-8 Aib residues in addition to L-residues that occur in proteins. The preliminary results of a crystal structure of alamethicin (Fox & Richards, 1982) showed that the 20-residue alamethicin molecule folds into a single helix that is predominantly a-helical. Recently, a published abstract concerning the crystal structure of trichorzianine (Le Bars et al., 1988) reports that its conformation is very similar to that of alamethicin. The replacement of the proton on the C “atom in an alanine residue with another methyl group severely restricts the pos-sible rotations about the NC “and C “-C'bonds. The torsion angles about these bonds are designated by and, respec-tively. In the manner of Ramachandran et al.(1963, 1968) for calculating allowable and space, Marshall and Bosshard (1972) and Burgess and Leach (1973) showed that the allowable and angles for the Aib residue occurred in two very restricted regions near-57,-47 and+ 57,+ 47.