Shanghai Food Safety and Engineering Technology Research Center, Bor S. Luh Food Safety Research Center, Key Lab of Urban Agriculture (South), School of Agriculture & Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
Shanghai Food Safety and Engineering Technology Research Center, Bor S. Luh Food Safety Research Center, Key Lab of Urban Agriculture (South), School of Agriculture & Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2020 Aug 5;236:118316. doi: 10.1016/j.saa.2020.118316. Epub 2020 Apr 13.
The binding of C-phycocyanin (CPC), a light harvesting pigment with phycocyanobilin (PCB), a chromophore is instrumental for the coloration and bioactivity. In this study, structure-mediated color changes of CPC from Spirulina platensis during various enzymatic hydrolysis was investigated based on UV-visible, circular dichroism, infra-red, fluorescence, mass spectrometry, and molecular docking. CPC was hydrolyzed using 7.09 U/mg protein of each enzyme at their optimal hydrolytic conditions for 3 h as follows: papain (pH 6.6, 60 °C), dispase (pH 6.6, 50 °C), and trypsin (pH 7.8, 37 °C). The degree of hydrolysis was in the order of papain (28.4%) > dispase (20.8%) > trypsin (7.3%). The sequence of color degradation rate and total color difference (ΔE) are dispase (82.9% and 40.37), papain (72.4% and 24.70), and trypsin (58.7% and 25.43). The hydrolyzed peptides were of diverse sequence length ranging from 8 to 9 residues (papain), 7-12 residues (dispase), and 9-63 residues (trypsin). Molecular docking studies showed that key amino acid residues in the peptides interacting with chromophore. Amino acid residues such as Arg86, Asp87, Tyr97, Asp152, Phe164, Ala167, and Val171 are crucial in hydrogen bonding interaction. These results indicate that the color properties of CPC might associate with chromopeptide sequences and their non-covalent interactions.
藻蓝蛋白（CPC）与藻蓝胆素（PCB）结合，是一种光收集色素，对于颜色和生物活性至关重要。在这项研究中，根据紫外可见分光光度法、圆二色性、红外、荧光、质谱和分子对接，研究了来自钝顶螺旋藻的 CPC 在各种酶水解过程中的结构介导的颜色变化。在每种酶的最佳水解条件下，使用 7.09 U/mg 蛋白质的每种酶将 CPC 水解 3 h，如下所示：木瓜蛋白酶（pH 6.6，60°C）、中性蛋白酶（pH 6.6，50°C）和胰蛋白酶（pH 7.8，37°C）。水解度的顺序为木瓜蛋白酶（28.4%）>中性蛋白酶（20.8%）>胰蛋白酶（7.3%）。颜色降解率和总色差（ΔE）的顺序为中性蛋白酶（82.9%和 40.37）、木瓜蛋白酶（72.4%和 24.70）和胰蛋白酶（58.7%和 25.43）。水解肽的序列长度从 8 到 9 个残基（木瓜蛋白酶）、7-12 个残基（中性蛋白酶）和 9-63 个残基（胰蛋白酶）不等。分子对接研究表明，与发色团相互作用的肽中的关键氨基酸残基。Arg86、Asp87、Tyr97、Asp152、Phe164、Ala167 和 Val171 等氨基酸残基在氢键相互作用中至关重要。这些结果表明，CPC 的颜色性质可能与色肽序列及其非共价相互作用有关。
