HYDROGEN-BONDING EFFECT ON C-13 NMR CHEMICAL-SHIFTS OF L-ALANINE RESIDUE CARBONYL CARBONS OF PEPTIDES IN THE SOLID-STATE
HYDROGEN-BONDING EFFECT ON C-13 NMR CHEMICAL-SHIFTS OF L-ALANINE RESIDUE CARBONYL CARBONS OF PEPTIDES IN THE SOLID-STATE
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DOI：
10.1021/ja00035a016
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发表时间：
1992-04-22
影响因子：
15
通讯作者：
OZAKI, T
中科院分区：
文献类型：
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作者：
ASAKAWA, N;KUROKI, S;OZAKI, T
为了研究固态肽中L-丙氨酸羰基碳的C-13 NMR化学位移与氢键长度之间的关系，测定了一系列含L-丙氨酸残基的肽的C-13 CP-MAS NMR谱，这些肽的晶体结构已由X射线衍射确定。从C-13化学位移的观测结果发现，L-丙氨酸残基的各向同性C-13化学位移（δ（iso））随氢键长度（R（N））的减小而线性地向低场移动。O））表示为delta（iso）= 237.5-21.7 R（N. 0)ppm. δ（iso）的这种低场位移主要来自δ-22的大的低场位移，δ-22是化学位移张量分量（δ-11，δ-22和δ-33）之一，随着R（N）的减小而减小。0）。Delta-11在R（N）的情况下有点向上移动。0)δ-33对R（N... 0）。用FPT-INDO方法对模型化合物的C-13屏蔽常数进行了量子化学计算，讨论了氢键对[C = O]中C-13化学位移的影响。讨论了H-N[型氢键及其性质。
In order to investigate the relationship between hydrogen-bond length and C-13 NMR chemical shifts of L-alanine carbonyl carbons in peptides in the solid state, C-13 CP-MAS NMR spectra were measured for a series of peptides containing L-alanine residues, for which the crystal structures were already determined by X-ray diffractions. From the results of the observed C-13 chemical shifts, it was found that the isotropic C-13 chemical shifts (delta(iso)) of L-alanine residues move linearly downfield with a decrease of hydrogen-bond length (R(N...O)) as expressed by delta(iso) = 237.5-21.7 R(N...0) ppm. Such a downfield shift of delta(iso) predominantly arises from the large downfield shift of delta-22, one of the chemical shift tensor components (delta-11, delta-22, and delta-33) with decreasing R(N...0). Delta-11 moves somewhat upfield with R(N...0) and delta-33 is not sensitive to a change of R(N...0). The quantum-chemical calculation of the C-13 shielding constant for the model compound was carried out by the FPT-INDO method, and the hydrogen-bonding effect on the C-13 chemical shift in the ]C = O...H-N[ type hydrogen bond and the nature of the hydrogen bond are discussed.