title: Unfolding/Refolding Study on Collagen from Sea Cucumber Based on 2D Fourier Transform Infrared Spectroscopy.
abstract: We aimed to explore the differences of thermal behaviors between insoluble collagen fibrils (ICFs) and pepsin-solubilized collagens (PSCs) from sea cucumberStichopus japonicus. The unfolding/refolding sequences of secondary structures of ICFs and PSCs during the heating and cooling cycle (5 → 70 → 5 °C) were identified by Fourier transform infrared spectrometry combined with curve-fitting and 2D correlation techniques. ICFs showed a higher proportion of α-helical structures and higher thermostability than PSCs, and thus had more-stable triple helical structures. The sequences of changes affecting the secondary structures during heating were essentially the same between ICFs and PSCs. In all cases, α-helix structure was the most important conformation and it disappeared to form a β-sheet structure. In the cooling cycle, ICFs showed a partially refolding ability, and the proportion of β-sheet structure rose before the increasing proportion of α-helix structure. PSCs did not obviously refold during the cooling stage.
authors.affiliation: School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, China. qinlei@dlpu.edu.cn.|National Engineering Research Center of Seafood, Dalian 116034, China. qinlei@dlpu.edu.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Qin
authors.affiliation: School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, China. bijingran125@163.com.|National Engineering Research Center of Seafood, Dalian 116034, China. bijingran125@163.com.|School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China. bijingran125@163.com.
authors.forename: Jing-Ran
authors.initials: JR
authors.lastname: Bi
authors.affiliation: School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, China. lidongmei@dlpu.edu.cn.|National Engineering Research Center of Seafood, Dalian 116034, China. lidongmei@dlpu.edu.cn.
authors.forename: Dong-Mei
authors.initials: DM
authors.lastname: Li
authors.affiliation: School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, China. i_Dongmeng@163.com.
authors.forename: Meng
authors.initials: M
authors.lastname: Dong
authors.affiliation: School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, China. 1201080407@cau.edu.cn.
authors.forename: Zi-Yuan
authors.initials: ZY
authors.lastname: Zhao
authors.affiliation: School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, China. dxiuping@163.com.|National Engineering Research Center of Seafood, Dalian 116034, China. dxiuping@163.com.
authors.forename: Xiu-Ping
authors.initials: XP
authors.lastname: Dong
authors.affiliation: School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, China. zdyzf1@163.com.|National Engineering Research Center of Seafood, Dalian 116034, China. zdyzf1@163.com.
authors.forename: Da-Yong
authors.initials: DY
authors.lastname: Zhou
authors.affiliation: School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, China. zhubeiwei@163.com.|National Engineering Research Center of Seafood, Dalian 116034, China. zhubeiwei@163.com.
authors.forename: Bei-Wei
authors.initials: BW
authors.lastname: Zhu
mesh_terms: D000596:Amino Acids; D000818:Animals; D003094:Collagen / Q000737:chemistry*; D011489:Protein Denaturation; D058849:Protein Refolding; D058767:Protein Unfolding; D012616:Sea Cucumbers / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics
chemical_list: D000596:Amino Acids; D003094:Collagen
keywords: 2D Fourier transform infrared spectrometry; insoluble collagen fibrils; pepsin-solubilized collagens; secondary structures; thermostability