Department of Chemistry, East Carolina University, Greenville, NC, USA.
FEBS Lett. 2022 Feb;596(3):350-359. doi: 10.1002/1873-3468.14275. Epub 2022 Jan 12.
Previous comparative kinetic isotope effects have inferred an allosteric site for fatty acids and their derivatives that modulates substrate selectivity in 15-lipoxygenases. Hydrogen-deuterium exchange also previously revealed regionally defined enhanced protein flexibility, centred at helix α2 - a gate to the substrate entrance. Direct evidence for allosteric binding and a complete understanding of its mechanism remains elusive. In this study, we examine the binding thermodynamics of the fatty acid mimic, oleyl sulfate (OS), with the monomeric model plant 15-LOX, soybean lipoxygenase (SLO), using isothermal titration calorimetry. Dynamic light scattering and differential scanning calorimetry rule out OS-induced oligomerization or structural changes. These data provide evidence that the fatty acid allosteric regulation of SLO is controlled by the dynamics of helix α2.
先前的比较动力学同位素效应推断出脂肪酸及其衍生物的变构结合位点，调节 15-脂氧合酶的底物选择性。氢氘交换先前也揭示了区域定义的增强的蛋白质灵活性，集中在螺旋 α2-底物入口的门。对于变构结合的直接证据及其机制的完整理解仍然难以捉摸。在这项研究中，我们使用等温滴定微量热法研究了脂肪酸类似物油酰硫酸盐（OS）与单体植物 15-脂氧合酶（SLO）大豆脂氧合酶的结合热力学。动态光散射和差示扫描量热法排除了 OS 诱导的寡聚化或结构变化。这些数据提供了证据表明，SLO 的脂肪酸变构调节受螺旋 α2 的动力学控制。
