A HIGH-RESOLUTION C-13-NMR STUDY OF COLLAGENLIKE POLYPEPTIDES AND COLLAGEN FIBRILS IN SOLID-STATE STUDIED BY THE CROSS-POLARIZATION MAGIC ANGLE-SPINNING METHOD - MANIFESTATION OF CONFORMATION-DEPENDENT C-13 CHEMICAL-SHIFTS AND APPLICATION TO CONFORMATIONAL CHARACTERIZATION
A HIGH-RESOLUTION C-13-NMR STUDY OF COLLAGENLIKE POLYPEPTIDES AND COLLAGEN FIBRILS IN SOLID-STATE STUDIED BY THE CROSS-POLARIZATION MAGIC ANGLE-SPINNING METHOD - MANIFESTATION OF CONFORMATION-DEPENDENT C-13 CHEMICAL-SHIFTS AND APPLICATION TO CONFORMATIONAL CHARACTERIZATION
复制标题
DOI：
10.1002/bip.360231111
复制
发表时间：
1984-01-01
期刊：
影响因子：
2.9
通讯作者：
MIYATA, T
中科院分区：
文献类型：
--
作者：
SAITO, H;TABETA, R;MIYATA, T
采用交叉极化魔角旋转（CP-MAS）方法记录了牛胶原纤维的固体高分辨13 C-NMR谱，并与胶原样多肽的13 C-NMR谱进行了对比分析。用两种模型多肽[（Gly）nII、（Pro）nII、（Hyp）n和（Ala.sbd.Gly.sbd.Gly）nII]和三螺旋多肽[（Pro.sbd.Gly.sbd.Pro）n和（Pro.sbd.Ala.sbd. Gly）n]测定胶原蛋白主要氨基酸残基（Gly、Pro、Ala和Hyp）的13 C化学位移。对这些多肽的13 C化学位移的检查以及先前的数据表明，在实验误差（±）内，各个氨基酸残基的13 C化学位移是相同的。0.5 ppm），如果构象相同的话。与α的那些相比，31-螺旋（Ala.sbd.Gly.sbd.Gly）n和三螺旋（Pro.sbd.Ala.sbd.Gly）n的Ala残基的13 C化学位移显着位移。-螺旋，β-片和丝I形成，并且可以用作检测胶原蛋白样多肽的构象特征的优良探针。此外，三螺旋多肽中Gly和Pro残基的13 C化学位移基本上从31-螺旋的（Gly）nII和（Pro）nII中发现的那些位移，反映了从31-螺旋到超螺旋三螺旋的进一步构象变化。特别地，三螺旋多肽的Gly C = O碳的13 C化学位移相对于31-螺旋多肽的化学位移基本上向高场位移（4.1- 5.1ppm）。这些位移被解释为前者的Gly C = O不参与NH ↑ [1]。cntdot.. C = O = C H键，而后者的该碳通过这些类型的H键连接。基于这些13 C化学位移，作为胶原样结构的参考数据，发现胶原原纤维的Gly、Ala、Pro和Hyp残基的13 C-NMR峰与上述模型多肽的预期值非常一致。一个合理的构象变化的胶原纤维在变性过程中进行了讨论。
High-resolution 13C-NMR spectra of bovine collagen fibrils in the solid state were recorded by the cross-polarization-magic-angle-spinning (CP-MAS) method and the spectra were analyzed with reference to those of collagen-like polypeptides. Two kinds of model polypeptides were used to obtain reference 13C chemical shifts of major amino acid residues of collagen (Gly, Pro, Ala and Hyp): the 31-helical polypeptides [(Gly)nII, (Pro)nII, (Hyp)n and (Ala.sbd.Gly.sbd.Gly)nII], and the triple-helical polypeptides [(Pro.sbd.Gly.sbd.Pro)n and (Pro.sbd.Ala.sbd.Gly)n]. Examination of the 13C chemical shifts of these polypeptides, together with the previous data, showed that the 13C chemical shifts of individual amino acid residues are the same, within experimental error (.+-. 0.5 ppm), among different polypeptides with different primary sequences, if the conformations are the same. The 13C chemical shifts of Ala residues of the 31-helical (Ala.sbd.Gly.sbd.Gly)n and triple-helical (Pro.sbd.Ala.sbd.Gly)n are significantly displaced, compared with those of the .alpha.-helix, .beta.-sheet and silk I form, and can be utilized as excellent probes to examine conformational features of collagen-like polypeptides. Further, the 13C chemical shifts of Gly and Pro residues in the triple-helical polypeptides are substantially displaced from those found in (Gly)nII and (Pro)nII of the 31-helix, reflecting further conformational change from the 31-helix to the supercoiled triple helix. In particular, the 13C chemical shifts of Gly C.dbd.O carbons of the triple-helical polypeptides are substantially displaced upfield (4.1-5.1 ppm), with respect to those of the 31-helical polypeptides. These displacements are interpreted by that Gly C.dbd.O of the former is not involved in NH.cntdot..cntdot..cntdot.O.dbd.C H-bonds, while this carbon of the latter is linked by these kinds of H-bonds. On the basis of these 13C chemical shifts, as reference data for the collagen-like structure, the 13C-NMR peaks of Gly, Ala, Pro and Hyp residues of collagen fibrils were found which are in good agreement with the values expected from the model polypeptides mentioned above. A plausible conformational change of collagen fibrils during denaturation is also discussed.