Zhang Zhi-Bao, Wang Jing-Jie, Chen Hui-Juan, Xiong Qing-Qing, Liu Ling-Rong, Zhang Qi-Qing
Guang Pu Xue Yu Guang Pu Fen Xi. 2014 Apr;34(4):1050-5.
In the present study, the authors explore the triple-helix conformation and thermal stability of collagen mimetic peptides (CMPs) as a function of peptide sequence and/or chain length by circular dichroism(CD). Five CMPs were designed and synthetized varying the number of POG triplets or incorporating an integrin alpha2beta1 binding motif Gly-Phe-Hyp-Gly-Glu-Arg (GFOGER). CD spectroscopy from 260 to 190 nm was recorded to confirm the existence of triple-helix conformation at room temperature, while thermal melting and thermal annealing of triple-helix (thermal unfolding and refolding of triple-helix, respectively) was characterized by monitoring ellipticity at 225 nm as a function of temperature. The results demonstrated that all the CMPs adopted triple-helix conformation, and the thermal stability of the CMPs was enhanced with increasing the number of POG triplets. In contrast to natural collagen, the thermal denaturation processes of CMPs were reversible, i. e. the triple-helix unfolded upon heating while refolded upon cooling. Meanwhile, the phenomenon of "hysteresis" was observed by comparing melting and thermal curves. These findings add new insights to the mechanisms of collagen and CMPs assembly, as well as provide an alternative approach to the fabrication of artificial collagen-likes biomaterials.
在本研究中，作者通过圆二色光谱法（CD）探究了胶原模拟肽（CMPs）的三螺旋构象和热稳定性与肽序列和/或链长的关系。设计并合成了五种CMPs，改变POG三联体的数量或引入整合素α2β1结合基序甘氨酸-苯丙氨酸-羟脯氨酸-甘氨酸-谷氨酸-精氨酸（GFOGER）。记录了260至190nm的CD光谱，以确认在室温下三螺旋构象的存在，同时通过监测225nm处的椭圆率随温度的变化来表征三螺旋的热熔化和热退火（分别为三螺旋的热解折叠和重折叠）。结果表明，所有CMPs均采用三螺旋构象，且随着POG三联体数量的增加，CMPs的热稳定性增强。与天然胶原不同，CMPs的热变性过程是可逆的，即三螺旋在加热时解折叠，而在冷却时重折叠。同时，通过比较熔化曲线和热曲线观察到了“滞后”现象。这些发现为胶原和CMPs组装机制增添了新的见解，也为制备人工胶原样生物材料提供了一种替代方法。
