De Oliveira Thomás Valente, Polêto Marcelo Depólo, Barbosa Samuel Vieira, Coimbra Jane Sélia Dos Reis, De Oliveira Eduardo Basílio
Departamento de Tecnologia de Alimentos (DTA), Universidade Federal de Viçosa (UFV), Campus Universitário, CEP 36570-900 Viçosa, MG, Brazil.
Departamento de Biologia Geral (DBG), Universidade Federal de Viçosa (UFV), Campus Universitário, CEP 36570-900 Viçosa, MG, Brazil.
Food Chem. 2022 Jan 15;367:130733. doi: 10.1016/j.foodchem.2021.130733. Epub 2021 Jul 30.
We used computational molecular dynamics (MD) to assess molecular conformations of apo- and holo-forms (respectively without and with Ca) of bovine α-lactalbumin (α-La) at different temperatures, and to correlate them with the protein's foaming properties. At 4 °C and 25 °C no major protein conformation changes occurred. At 75 °C, lots of changes were evidenced: the Ca depletion triggered the complete loss of h2b, h3c helices and S1, S2 and S3 β-sheets, and partial losses of H1, H2 and H3 α-helices. The absence of Ca in apo-α-La and its leaving from holo-α-La triggered electrostatic repulsion among Asp82, Asp84 and Asp87, leading to the formation of a hydrophobic cluster involving Phe9, Phe31, Ile1, Va42, Ile55, Phe80 and Leu81. These conformational changes were related to an interfacial tension decrease and to a foaming capacity increase, for both apo-α-La and holo-α-La. This study exemplifies how powerful MD is as a tool to provide a better understanding of the molecular origins of food proteins' techno-functionalities.
我们运用计算分子动力学（MD）来评估牛α-乳白蛋白（α-La）的脱辅基形式和全蛋白形式（分别为不含钙和含钙形式）在不同温度下的分子构象，并将其与蛋白质的起泡特性相关联。在4°C和25°C时，未发生主要的蛋白质构象变化。在75°C时，出现了许多变化：钙的缺失引发了h2b、h3c螺旋以及S1、S2和S3β-折叠的完全丧失，以及H1、H2和H3α-螺旋的部分丧失。脱辅基α-La中钙的缺失及其从全蛋白α-La中的脱离引发了Asp82、Asp84和Asp87之间的静电排斥，导致形成了一个涉及Phe9、Phe31、Ile1、Va42、Ile55、Phe80和Leu81的疏水簇。这些构象变化与脱辅基α-La和全蛋白α-La的界面张力降低以及起泡能力增强有关。这项研究例证了MD作为一种工具在更好地理解食品蛋白质技术功能的分子起源方面的强大作用。
