Roy Alankar, Paul Ishani, Chakraborty Priyanka, Saha Adrija, Ray Sujay
Amity Institute of Biotechnology, Amity University, Kolkata, India.
Amity Institute of Biotechnology, Amity University, Kolkata, India.
Biochim Biophys Acta Gen Subj. 2025 Mar;1869(3):130766. doi: 10.1016/j.bbagen.2025.130766. Epub 2025 Jan 19.
Metabolic dysfunction-associated steatotic liver disease (MASLD) covers a range of liver conditions marked by the buildup of fat, spanning from simple fatty liver to more advanced stages like metabolic dysfunction-associated steatohepatitis and cirrhosis.
Our in-depth analysis of PNPLA3_WT and mutants (I148M (MT1) and C15S (MT2)) provides insights into their structure-function dynamics in lipid metabolism, especially lipid droplet hydrolysis and ABHD5 binding. Employing molecular docking, binding affinity, MD analysis, dissociation constant, and MM/GBSA analysis, we delineated distinct binding characteristics between wild-type and mutants.
Structural dynamics analysis revealed that unbound mutants exhibited higher flexibility, increased R and SASA values, and broader energy landscapes, indicating multiple inactive states. Mutations, especially in PNPLA3_MT1, reduced the exposure of the catalytic serine, potentially impairing enzymatic activity and LD hydrolysis efficiency. Altered interaction patterns and dynamics, particularly a shift in ABHD5 binding regions towards the C-terminal domain, underscore its role in LD metabolism. Energy dynamics analysis of the protein complexes revealed PNPLA3_WT exhibited multiple low-energy macrostates, whereas the mutants displayed narrower energy landscapes, suggesting a more stable functional state. PNPLA3_MT1 demonstrated the highest affinity towards ABHD5, highlighting the complex interplay between protein structure, dynamics, and lipid metabolism regulation.
PNPLA3_MT1 mutant exhibits the highest flexibility and significantly reduced catalytic serine accessibility, leading to impaired lipolysis. Contrarily, PNPLA3_WT maintains stable catalytic efficiency and effective LD hydrolysis, with PNPLA3_MT2 displaying intermediate behavior.
Our research provides valuable insights into the metabolic implications of PNPLA3 mutations, offering a path for potential therapeutic interventions in MASLD.
代谢功能障碍相关脂肪性肝病（MASLD）涵盖一系列以脂肪堆积为特征的肝脏疾病，范围从单纯性脂肪肝到更晚期阶段，如代谢功能障碍相关脂肪性肝炎和肝硬化。
我们对PNPLA3_WT及其突变体（I148M（MT1）和C15S（MT2））进行了深入分析，以深入了解它们在脂质代谢中的结构-功能动态，特别是脂滴水解和ABHD5结合。通过分子对接、结合亲和力、分子动力学分析、解离常数和MM/GBSA分析，我们描绘了野生型和突变体之间不同的结合特征。
结构动力学分析表明，未结合的突变体表现出更高的灵活性、增加的R和溶剂可及表面积值以及更宽的能量景观，表明存在多种非活性状态。突变，尤其是PNPLA3_MT1中的突变，减少了催化丝氨酸的暴露，可能损害酶活性和脂滴水解效率。相互作用模式和动力学的改变，特别是ABHD5结合区域向C末端结构域的转移，强调了其在脂滴代谢中的作用。蛋白质复合物的能量动力学分析表明，PNPLA3_WT表现出多种低能量宏观状态，而突变体的能量景观较窄，表明功能状态更稳定。PNPLA3_MT1对ABHD5表现出最高亲和力，突出了蛋白质结构、动力学和脂质代谢调节之间的复杂相互作用。
PNPLA3_MT1突变体表现出最高的灵活性，催化丝氨酸可及性显著降低，导致脂解受损。相反，PNPLA3_WT保持稳定的催化效率和有效的脂滴水解，PNPLA3_MT2表现出中间行为。
我们的研究为PNPLA3突变的代谢影响提供了有价值的见解，为MASLD的潜在治疗干预提供了一条途径。
