Kanaori K, Nosaka A Y
International Research Laboratories, Ciba-Geigy Japan Ltd., Takarazuka, Japan.
Biochemistry. 1995 Sep 26;34(38):12138-43. doi: 10.1021/bi00038a006.
The fibrillation of human calcitonin (hCT) has been investigated by NMR in aqueous solution. The time course of proton one- and two-dimensional NMR spectra of hCT (80 mg/mL at pH 2.9) was measured during the fibrillation. It showed a gradual broadening of the peptide peaks, followed by a rapid broadening and subsequent disappearance of the peaks. The gradual broadening can be attributed to equilibrium between monomer and associated hCT, whereas the rapid broadening can be attributed to formation of aggregates and to gelation of the peptide solution. All the peptide peaks did not broaden and disappear simultaneously. Peaks of residues in the N-terminal (Cys1-Cys7) and central (Met 8-Pro23) regions broadened and disappeared faster during the gradual broadening than those in the C-terminal region (Gln24-Pro32). Moreover, in the N-terminal and central residues, peaks of Cys1, Leu4,9, Met 8, Tyr12, Asp15, and Phe16,19,22 disappeared faster than those of Asn3,17, Ser5, Cys7, Gln14, Lys18, and His20. Hydrogen-deuterium exchange of amide protons indicated the formation of hydrogen bonds caused by association of hCT molecules. The amphiphilicity of the peptide appears to be important for the hCT association.
已通过核磁共振（NMR）在水溶液中研究了人降钙素（hCT）的纤维化过程。在纤维化过程中测量了hCT（pH 2.9时浓度为80 mg/mL）的质子一维和二维核磁共振谱的时间进程。结果显示肽峰逐渐变宽，随后迅速变宽并随后消失。逐渐变宽可归因于单体与缔合hCT之间的平衡，而迅速变宽可归因于聚集体的形成以及肽溶液的凝胶化。并非所有肽峰同时变宽并消失。在逐渐变宽过程中，N端（Cys1-Cys7）和中间（Met 8-Pro23）区域的残基峰比C端区域（Gln24-Pro32）的峰变宽和消失得更快。此外，在N端和中间残基中，Cys1、Leu4、9、Met 8、Tyr12、Asp15以及Phe16、19、22的峰比Asn3、17、Ser5、Cys7、Gln14、Lys18和His20的峰消失得更快。酰胺质子的氢-氘交换表明hCT分子缔合导致氢键形成。该肽的两亲性似乎对hCT缔合很重要。
