Determination of intrinsic hydrophilicity/hydrophobicity of amino acid side chains in peptides in the absence of nearest-neighbor or comformational effects
Determination of intrinsic hydrophilicity/hydrophobicity of amino acid side chains in peptides in the absence of nearest-neighbor or comformational effects
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DOI：
10.1002/bip.20417
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发表时间：
2006-01-01
期刊：
影响因子：
2.9
通讯作者：
Hodges, RS
中科院分区：
文献类型：
--
作者：
Kovacs, JM;Mant, CT;Hodges, RS
了解肽/蛋白质中氨基酸侧链的亲水性/疏水性是生物学最重要的方面之一。尽管已经产生了许多疏水性/疏水性尺度，但尚未实现所有“固有”尺度。 “内在的”意指在不存在最近邻效应或构象效应的情况下侧链的最大可能的亲水性/疏水性，当侧链位于多肽链中时，最近邻效应或构象效应会降低侧链亲水性/疏水性的完全表达。这样的尺度是确定影响侧链疏水性的参数以及量化肽和蛋白质中的此类影响的基本起点。 10 个残基肽序列 Ac-X-G-A-K-G-A-G-V-G-L-酰胺被设计用于确定内在值，其中 X 位置被所有 20 个天然存在的氨基酸以及正缬氨酸、正亮氨酸和鸟氨酸取代。系数通过反相高效液相色谱法确定，使用六种不同的流动相条件，包括不同的 pH 值（2、5 和 7）、离子对试剂以及是否存在不同的盐。结果表明，肽（蛋白质）中氨基酸侧链的固有亲水性/疏水性与 pH、缓冲条件或 17 种侧链（Gly、Ala、Cys、Pro、Val、nVal、Len.nLeu、Ile、Met、Tyr、Phe、Trp、Ser、Thr、Asn 和 Gln）是否使用 C-8 at、C-18 反相柱无关。 取决于 pH 值和缓冲液条件，包括潜在带电侧链（Orn、Lys、His、Arg、Asp 和 Glu）的盐或离子对试剂的类型。 (c) 2005 年 Wiley 期刊公司。
Understanding the hydrophilicity/hydrophobicity of amino acid side chains in peptides/proteins is one the most important aspects of biology. Though many hydrophobilicity/hydrophobicity scales have been generated, all "intrinsic" scale has yet to be achieved. "Intrinsic" implies the maximum possible hydrophilicity/hydrophobicity of side, chains in the absence of nearest-neighbor or conformational effects that would decrease the full expression of the side-chain hydrophilicity/hydrohobicity when the side chain is in a polypeptide chain. Such a scale is the fundamental starting point for determining the parameters that affect side-chain hydrophobicity and for quantifying such effects in peptides and proteins. A 10-residue peptide sequence, Ac-X-G-A-K-G-A-G-V-G-L-amide, was designed to enable the determination of the intrinsic values, where position X was substituted by all 20 naturally occurring amino acids and norvaline, norleucine, and ornithine. The coefficients were determined by reversed-phase high-performance liquid chromatography using six different mobile phase conditions involving different pH values (2, 5, and 7), ion-pairing reagents, and the presence and absence of different salts. The results show that the intrinsic hydrophilicity/hydrophobicity of amino acid side chains in peptides (proteins) is independent of pH, buffer conditions, or whether C-8 at, C-18 reversed-phase columns were used for 17 side chains (Gly, Ala, Cys, Pro, Val, nVal, Len. nLeu, Ile, Met, Tyr, Phe, Trp, Ser, Thr, Asn, and Gln) and dependent on pH and buffer conditions, including the type of salt or ion-pairing reagent for potentially charged side chains (Orn, Lys, His, Arg, Asp, and Glu). (c) 2005 Wiley Periodicals, Inc.