Study of Collagen Mimetic Peptide’s Triple-Helix Structure and Its Thermostability by Circular Dichroism
ZHANG Zhi-bao1, WANG Jing-jie1, CHEN Hui-juan1, XIONG Qing-qing1, LIU Ling-rong1*, ZHANG Qi-qing1，2*
1. Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Biomedical Material of Tianjin, Tianjin 300192, China 2. Institute of Biomedical and Pharmaceutical Technology, Fuzhou University, Fuzhou 350002, China
Abstract：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 α2β1 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.
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