biomolecules Article Transient Unfolding and Long-Range Interactions in Viral BCL2 M11 Enable Binding to the BECN1 BH3 Domain Arvind Ramanathan 1,2,*, Akash Parvatikar 3, Srinivas C. Chennubhotla 3,* and Yang Mei 4,† and Sangita C. Sinha 4,* 1 Data Science and Learning Division, Argonne National Laboratory, Lemont, IL 60439, USA 2 Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL 60637, USA 3 Department of Computational and Systems Biology, University of Pittsburgh, PA 15260, USA;
[email protected] 4 Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108, USA;
[email protected] * Correspondence:
[email protected] (A.R.);
[email protected] (S.C.C.);
[email protected] (S.C.S.); Tel.: +1-630-252-3805 (A.R.); +1-412-648-7794 (S.C.C.); +1-701-231-5658 (S.C.S.) † Current address: The Wistar Institute, Philadelphia, PA 19104, USA. Received: 27 July 2020; Accepted: 4 September 2020; Published: 11 September 2020 Abstract: Viral BCL2 proteins (vBCL2s) help to sustain chronic infection of host proteins to inhibit apoptosis and autophagy. However, details of conformational changes in vBCL2s that enable binding to BH3Ds remain unknown. Using all-atom, multiple microsecond-long molecular dynamic simulations (totaling 17 µs) of the murine g-herpesvirus 68 vBCL2 (M11), and statistical inference techniques, we show that regions of M11 transiently unfold and refold upon binding of the BH3D. Further, we show that this partial unfolding/refolding within M11 is mediated by a network of hydrophobic interactions, which includes residues that are 10 Å away from the BH3D binding cleft.