[3P-1] Poster 3 (3P-01ー3P-47)

[3P-36] Structure analysis by data assimilation using ion mobility mass spectrometry and molecular simulation: Application to H2A-H2B dimer

Kazumi Saikusa^1,2, Satoko Akashi², ^○Sotaro Fuchigami³ (1.NMIJ, AIST, 2.Grad. Sch. of Med. Life Sci., Yokohama City Univ., 3.Grad. Sch. of Science, Kyoto Univ.)

Ion mobility-mass spectrometry (IM-MS) is a powerful tool for simultaneous analysis of mass, charge, and collision cross-section (CCS) of biomolecules. In our previous studies, we characterized the gas-phase structures of biomolecular complexes using IM-MS and all-atom molecular dynamics (MD) simulation. However, it is not easy to perform all-atom MD simulations of biomolecular complexes with intrinsically disordered regions (IDRs), such as histone H2A-H2B dimer with flexible tails, because it requires high computational cost due to the flexibility of IDRs. In this study, we used coarse-grained MD (CG-MD) simulation instead of all-atom MD simulation to obtain an appropriate structural ensemble of H2A-H2B dimer that matches the experimental CCS distribution obtained by IM-MS. The obtained structural ensemble gave CCS values in the range of 2,130-2,590 Angstrom², within which experimental values are comprised. However, the obtained CCS distribution was unimodal, even though experimental IM-MS observations showed a bimodal CCS distribution. To resolve this discrepancy, we also performed CG-MD simulations including interactions between the histone core and tails, resulting in a bimodal CCS distribution successfully.