三种淡水鱼皮胶原蛋白膜机械性能和α1链一级结构的相关性研究

Correlation between Mechanical Properties of Three Freshwater Fish Skin Collagen Films and the Primary Structure of the α1Chain in Collagen

摘要:

本文探究了三种淡水鱼皮胶原蛋白膜的机械性能和胶原α1链一级结构之间的相关性。结果发现，利用罗非鱼皮胶原制备的蛋白膜的抗拉伸强度可以达到51.24 MPa，高于鲢鱼和草鱼皮胶原制备的蛋白膜，且色泽更接近白色。在三种鱼皮胶原溶液的圆二色光谱（CD光谱）中正负吸收峰强度比的绝对值(RPN值)存在明显差异，但在胶原蛋白膜的CD光谱中RPN值却较接近。另一方面，利用RT-PCR和RACE的方法克隆了鲢鱼胶原α1链(COL1A1)基因，结果获得COL1A1cDNA全长4923 bp（NCBI序列号：KJ848743），编码1448个氨基酸；系统进化树分析结果表明鲢鱼和草鱼COL1A1序列属于同一分支，与罗非鱼的遗传距离较远。根据三种胶原α1链一级结构的分析结果，发现罗非鱼胶原α1链的C-前肽和三螺旋结构域中G-X-Y序列中含有更多的Pro，因此罗非鱼皮胶原可以形成高强度的蛋白膜。

Abstract:

The study aimed to investigate the correlation between mechanical properties of three freshwater fish skin collagen films and the primary structure of the collagen α1 chain (COL1A1). The results showed that the tensile strength of tilapia skin collagen films reached up to 51.24 MPa, which was higher than those of the silver carp and grass carp skin films. Moreover, the color values of tilapia skin collagen films were closer to those of a white standard plate. Significant differences were observed in the ratios of positive to negative peak (RPN) calculated from the circular dichroism (CD) spectra of the three types of fish collagen solutions, while similar RPN values were observed in the resulting collagen films. Furthermore, the silver carp COL1A1 gene sequence was cloned using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The 4923-bp full-length cDNA of silver carp COL1A1 (GenBank No. KJ848743) was obtained, which encoded 1448 amino acids. The constructed phylogenetic tree showed that the COL1A1 sequences of silver carp and grass carp clustered together, but were distant from that of tilapia. The analysis of the primary structure of COL1A1 indicated that there were more proline residues in the C-peptide and G-X-Y sequences of the triple-helical domain of tilapia COL1A1; therefore, strong collagen films could be formed using tilapia skins.