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首页> 外文期刊>Biophysical Chemistry: An International Journal Devoted to the Physical Chemistry of Biological Phenomena >1H-NMR parameters of common amino acid residues measured in aqueous solutions of the linear tetrapeptides Gly-Gly-X-Ala at pressures between 0.1 and 200 MPa.
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1H-NMR parameters of common amino acid residues measured in aqueous solutions of the linear tetrapeptides Gly-Gly-X-Ala at pressures between 0.1 and 200 MPa.

机译：在线性线性四肽Gly-Gly-X-Ala水溶液中在0.1至200 MPa的压力下测量的常见氨基酸残基的1H-NMR参数。

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摘要

For the interpretation of chemical shift changes induced by pressure in proteins, a comparison with random-coil data is important. For providing such a data basis, the pressure dependence of the 1H-NMR chemical shifts of the amino acids X in the random-coil model peptides Gly-Gly-X-Ala were studied for the 20 common amino acids at two pH values (pH 5.0 and 5.4) at 305 K, in the pressure range from 0.1 to 200 MPa. The largest shift changes Deltadelta with pressure p can be observed for the backbone amide protons. The average linear pressure coefficient delta(Deltap) is 0.38 ppm GPa(-1), with a root mean square deviation of 0.2 ppm GPa(-1). In contrast to the downfield shift typical for amide protons, the H(alpha)-resonances typically shift upfield, with a pressure coefficient of -0.025 ppm GPa(-1) and a root mean square deviation of 0.05 ppm GPa(-1). The side chain resonances are only weakly influenced by pressure, on average they are shifted by 0.014 ppm GPa(-1(,)) with a root mean square deviation of 0.14 ppm GPa(-1). The exceptions are the side chain amide protons of asparagine and glutamine. Here, values of 0.214 (Asn H(delta21)), 0.417 (Asn H(delta22)), 0.260 (Gln H(varepsilon21)) and 0.395 (Gln H(varepsilon22)) ppm GPa(-1) can be observed. In both cases, the pressure dependent shift is larger for the pro-E proton than for the pro-Z proton. Within the limits of error the equilibrium constant for the trans- and cis-conformers at the proline peptide bond is independent of pressure in the pressure range studied.
机译：为了解释蛋白质压力引起的化学位移变化，与随机螺旋数据进行比较很重要。为了提供这样的数据基础，研究了在两个pH值（pH值）下，随机螺旋模型肽Gly-Gly-X-Ala中氨基酸X的1H-NMR化学位移的压力依赖性。 5.0和5.4）在305 K的压力范围从0.1到200 MPa。对于主链酰胺质子，可以观察到随压力p的最大变化变化量Δδ。平均线性压力系数delta（Deltap）为0.38 ppm GPa（-1），均方根偏差为0.2 ppm GPa（-1）。与酰胺质子典型的下场偏移相反，Hα共振通常向上场偏移，压力系数为-0.025 ppm GPa（-1），均方根偏差为0.05 ppm GPa（-1）。侧链共振仅受压力的微弱影响，它们平均偏移0.014 ppm GPa（-1（，）），均方根偏差为0.14 ppm GPa（-1）。天冬酰胺和谷氨酰胺的侧链酰胺质子除外。在这里，可以观察到0.214（Asn H（δ21）），0.417（Asn H（δ22）），0.260（Gln H（varepsilon21））和0.395（Gln H（varepsilon22））ppm GPa（-1）的值。在这两种情况下，pro-E质子的压力相关位移均大于pro-Z质子。在误差范围内，脯氨酸肽键上反式和顺式异构体的平衡常数与所研究压力范围内的压力无关。

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