Analysis of AlphaFold and molecular dynamics structure predictions of mutations in serpins

Serine protease inhibitors (serpins) include thousands of structurally conserved proteins playing key roles in many organisms. Mutations affecting serpins may disturb their conformation, leading to inactive forms. Unfortunately, conformational consequences of mutations affecting serpins are difficult to predict. In this study we integrate experimental data of patients with mutations affecting one serpin with the predictions obtained by AlphaFold and molecular dynamics. Five SERPINC1 mutations causing antithrombin deficiency, the strongest congenital thrombophilia, (p.Arg79Cys; p.Pro112Ser, p.Met283Val; p.Pro352insValPheLeuPro, and p.Glu241_Leu242delinsValLeuValLeuValAsnThrArgThr-Ser) were selected from a cohort of 350 unrelated patients based on functional, biochemical, and crystallographic evidence supporting a folding defect. AlphaFold gave an accurate prediction for the wild-type antithrombin structure. However, it only produced native structures for all variants, regardless of its complexity and in-vivo conformational consequences. Similarly, molecular dynamics of up to 1000 ns at temperatures that caused conformational transitions did not show significant changes in the native structure of wild-type or variants. In conclusion, one predictive tool of protein folding, AlphaFold, and a simulation method for analyzing the physical movements of atoms and molecules, molecular dynamics, force predictions into the native stressed conformation at conditions with experimental evidence supporting a conformational change to relaxed structures. It is necessary to improve predictive strategies for serpins that consider the conformational sensitivity of these molecules.