13C/1H high power double magnetic resonance investigation of collagen backbone motion in fibrils and in solution.
13C/1H high power double magnetic resonance investigation of collagen backbone motion in fibrils and in solution.
复制标题
原纤维和溶液中胶原骨架运动的 13C/1H 高功率双磁共振研究。
DOI：
10.1016/0022-2836(79)90250-x
复制
发表时间：
1979
影响因子：
5.6
通讯作者：
D. Torchia
中科院分区：
文献类型：
--
作者：
L. Jelinski;D. Torchia
Abstract 13 C 1 H high power double magnetic resonance spectroscopy was used to investigate the mobility of the collagen peptide backbone.[1-13 C]-and [2-13 C]-glycine-labeled collagen samples (with> 50% enrichment in 13 C) were prepared via chick calvaria culture. 13 C nmr† spectra of labeled reconstituted collagen fibrils, of labeled helical collagen in solution, and of unlabeled bovine Achilles tendon collagen were obtained with scalar decoupling and with dipolar decoupling of protons. Proton-enhanced spectra were also obtained using cross-polarization techniques. nmr parameters (linewidths, lineshapes, T 1 values, nuclear Overhauser enhancements, and cross polarization enhancements) were measured for the labeled samples and for collagen in natural abundance. Comparison of 13 C nmr parameters for bovine Achilles tendon fibrils and for reconstituted chick calvaria collagen fibrils established that chick calvaria collagen is a good model for the molecular dynamics of collagen in vivo. Spin-lattice relaxation times and nuclear Overhauser enhancements for [1-13 C]-and [2-13 C] glycine-labeled collagen indicated that R 1~ 2× 10 7 s− 1 in solution, where R 1 is the diffusion constant for reorientation about the long axis of the molecule. A substantially smaller value for R 1 (2.6× 10 6 s− 1) was calculated for an axially symmetric ellipsoid of revolution having dimensions appropriate to the collagen helix. The discrepancy between the rigid ellipsoid and nmr values of R 1 suggests that the collagen molecule undergoes torsional reorientation, as well as rod-like reorientation, about its long axis. The T 1 and NOE values measured in the glycine-labeled fibrils show that rapid axial motion (R 1~ 10 7 s− 1) persists in the fibrillar state. In the collagen fibril the full width of the glycyl carbonyl powder pattern is 103 ppm This value is substantially smaller than the rigid lattice value, 144 ppm, which provides further evidence for motion in the fibril. The observed powder pattern is axially asymmetric, which shows that certain azimuthal orientations are energetically preferred in the fibril. Taken together, the nmr data provide strong evidence that rapid reorientation of the helix backbone occurs in the fibrils. This result shows that formation of a fibrillar structure does not require the existence of a unique set of intermolecular interactions at the helical surfaces.
