Food Protein Research and Development Center, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety , South China University of Technology , Guangzhou 510640 , P. R China.
J Agric Food Chem. 2018 May 16;66(19):4913-4922. doi: 10.1021/acs.jafc.8b00414. Epub 2018 Apr 13.
To understand the underlying molecular mechanism of the cholesterol-lowering effect of soybean 7S globulins, the interactions of their pepsin-released peptides (7S-peptides) with cell membrane models consisting of dipalmitoylphosphatidylcholine (DPPC), dioleoylphosphatidylcholine (DOPC), and cholesterol (CHOL) were systematically studied. The results showed that 7S-peptides were bound to DPPC/DOPC/CHOL liposomes mainly through van der Waals forces and hydrogen bonds, and the presence of higher CHOL concentrations enhanced the binding affinity (e.g., DPPC/DOPC/CHOL = 1:1:0, binding ratio = 0.114; DPPC/DOPC/CHOL = 1:1:1, binding ratio = 2.02). Compression isotherms indicated that the incorporation of 7S-peptides increased the DPPC/DOPC/CHOL monolayer fluidity and the lipid raft size. The presence of CHOL accelerated the 7S-peptide accumulation on lipid rafts, which could serve as platforms for peptides to develop into β-sheet rich structures. These results allow us to hypothesize that 7S-peptides may indirectly influence membrane protein functions via altering the membrane organization in the enterocytes.
为了理解大豆 7S 球蛋白降低胆固醇作用的潜在分子机制，系统研究了其胃蛋白酶释放肽（7S-肽）与由二棕榈酰磷脂酰胆碱（DPPC）、二油酰基磷脂酰胆碱（DOPC）和胆固醇（CHOL）组成的细胞膜模型的相互作用。结果表明，7S-肽主要通过范德华力和氢键与 DPPC/DOPC/CHOL 脂质体结合，较高的 CHOL 浓度增强了结合亲和力（例如，DPPC/DOPC/CHOL = 1:1:0，结合比 = 0.114；DPPC/DOPC/CHOL = 1:1:1，结合比 = 2.02）。压缩等温线表明，7S-肽的掺入增加了 DPPC/DOPC/CHOL 单层的流动性和脂筏的大小。CHOL 的存在加速了 7S-肽在脂筏上的积累，这可以作为肽形成富含β-折叠结构的平台。这些结果使我们假设 7S-肽可能通过改变肠细胞中的膜组织间接影响膜蛋白的功能。
