Ding Ning, Jiang Yaoyukun, Ge Robbie, Shao Qianzhen, Shin Wook, Ran Xinchun, Yang Zhongyue J
Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA.
Center for Structural Biology, Vanderbilt University, Nashville, TN, 37235, USA.
Angew Chem Int Ed Engl. 2025 Jul;64(29):e202505991. doi: 10.1002/anie.202505991. Epub 2025 May 9.
Cold-adapted bidomain enzymes have the potential to foster industrial sustainability by reducing energy consumption and greenhouse gas emissions. Despite their allure, these benefits are unattainable, as the molecular basis of cold adaptation remains elusive, and there are no strategies to guide the acquisition of this behavior. To uncover principles of cold adaptation, we selected the cold-adapted Saccharophagus degradans amylase (sdA) and mesophilic Pseudomonas saccharophila amylase (psA) as model systems. Through molecular dynamics (MD) simulations and biochemical assays, we found that sdA exhibits significantly greater interdomain separation between its catalytic domain (CD) and carbohydrate-binding module (CBM) at low temperatures. Therefore, we introduce the domain separation index metric to guide the in silico screening of 120 psA variants using high-throughput enzyme modeling. The highest-ranked variant, psA121, shows a 3-fold increase in relative activity over the wild type at 0 °C. MD simulations suggest that psA121 achieves cold adaptation via helical linkers, which induce interdomain separation and enhance flexibility of the active site and binding loops via dynamic allostery, promoting substrate recruitment, binding, and catalysis at lower temperatures. This study highlights how domain separation contributes to cold adaptation in bidomain amylases and offers strategies for introducing such cold adaptation to other systems.
冷适应双结构域酶具有通过降低能源消耗和温室气体排放来促进工业可持续发展的潜力。尽管它们具有吸引力,但这些益处难以实现,因为冷适应的分子基础仍然难以捉摸,而且没有策略来指导获得这种特性。为了揭示冷适应的原理,我们选择了冷适应的嗜糖栖热袍菌淀粉酶(sdA)和嗜温的嗜糖假单胞菌淀粉酶(psA)作为模型系统。通过分子动力学(MD)模拟和生化分析,我们发现sdA在低温下其催化结构域(CD)和碳水化合物结合模块(CBM)之间表现出明显更大的结构域间分离。因此,我们引入了结构域分离指数指标,以指导使用高通量酶建模对120个psA变体进行计算机筛选。排名最高的变体psA121在0°C时的相对活性比野生型增加了3倍。MD模拟表明,psA121通过螺旋连接子实现冷适应,螺旋连接子通过动态变构诱导结构域间分离,并增强活性位点和结合环的灵活性,从而在较低温度下促进底物募集、结合和催化。这项研究突出了结构域分离如何促进双结构域淀粉酶的冷适应,并为将这种冷适应引入其他系统提供了策略。