Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky Str., 420111, Kazan, Russia; Sirius University of Science and Technology, 1 Olympic Ave, 354340, Sochi, Russia.
Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky Str., 420111, Kazan, Russia; Sirius University of Science and Technology, 1 Olympic Ave, 354340, Sochi, Russia.
Carbohydr Polym. 2021 Jan 15;252:117181. doi: 10.1016/j.carbpol.2020.117181. Epub 2020 Oct 5.
The interactions between κ-carrageenan and hen egg-white lysozyme have been studied. In dilute solutions, the insoluble complexes with constant κ-carrageenan/lysozyme ratio of 0.3, or 12 disaccharide units per mole of protein are formed. FTIR-spectroscopy revealed that κ-carrageenan retains its unordered conformation and induces the rise of β-structure in lysozyme. In the complexes formed in concentrated mixtures, κ-carrageenan adopts helical conformation and lysozyme retains its native-like structure. These complexes contain 21 disaccharide units per mole of protein. Molecular modeling showed that flexible coil and rigid double helix of κ-carrageenan have different binding patterns to lysozyme surface. The latter has a strong preference to positively charged spots in lysozyme α-domain while the former also interacts to protein β-domain and stabilizes short-living β-structures. The obtained results confirm the preference of unordered κ-carrageenan to β-structure rich protein regions, which can be further used in the development of carrageenan-based protection of amyloid-like aggregation of proteins.
已经研究了κ-卡拉胶与蛋清溶菌酶之间的相互作用。在稀溶液中，形成了不溶性复合物，其κ-卡拉胶/溶菌酶的比例为 0.3，或每摩尔蛋白质有 12 个二糖单位。傅里叶变换红外光谱（FTIR）表明，κ-卡拉胶保留了其无规构象，并诱导溶菌酶中β-结构的增加。在浓混合物中形成的复合物中，κ-卡拉胶采用螺旋构象，而溶菌酶保留其类似天然的结构。这些复合物每摩尔蛋白质含有 21 个二糖单位。分子建模表明，κ-卡拉胶的柔性线圈和刚性双螺旋具有不同的与溶菌酶表面结合模式。后者对溶菌酶α-结构域中的正电荷点有强烈的偏好，而前者也与蛋白质β-结构域相互作用，并稳定短暂的β-结构。所得结果证实了无规κ-卡拉胶对富含β-结构的蛋白质区域的偏好，这可进一步用于基于卡拉胶的蛋白质类似淀粉样聚集保护的开发。
