8SM5

Crystal Structure of BHRF1 from Epstein Barr Virus in complex with BID BH3 peptide

Summary for 8SM5

• Entry DOI: 10.2210/pdb8sm5/pdb
• Descriptor: Apoptosis regulator BHRF1, BID BH3 (3 entities in total)
• Functional Keywords: bhrf1, bid peptide, complex, viral protein, bh3 domain, apoptosis
• Biological source: Human herpesvirus 4 strain B95-8 (Epstein-Barr virus (strain B95-8), Human herpesvirus 4 (strain B95-8)); More
• Total number of polymer chains: 10
• Total formula weight: 99727.56

Authors

Wyatt, S.,Sinha, S. (deposition date: 2023-04-25, release date: 2023-10-11, Last modification date: 2024-03-06)

Primary citation

Wyatt, S.,Glover, K.,Dasanna, S.,Lewison, M.,Gonzalez-Garcia, M.,Colbert, C.L.,Sinha, S.C.
Epstein-Barr Virus Encoded BCL2, BHRF1, Downregulates Autophagy by Noncanonical Binding of BECN1.
Biochemistry, 62:2934-2951, 2023

PubMed Abstract: γ-herpesviruses (γHVs) encode BCL2 homologues (vBCL2) that bind the Bcl-2 homology 3 domains (BH3Ds) of diverse proteins, inhibiting apoptosis and promoting host cell and virus survival. vBCLs encoded by Kaposi sarcoma-associated HV (KSHV) and γHV68 downregulate autophagy, a degradative cellular process crucial for homeostasis and innate immune responses to pathogens, by binding to a BH3D in BECN1, a key autophagy protein. Epstein-Barr virus (EBV) encodes a vBCL2 called BHRF1. Here we show that unlike the KSHV and γHV68 vBCL2s, BHRF1 does not bind the isolated BECN1 BH3D. We use yeast two-hybrid assays to identify the minimal region of BECN1 required and sufficient for binding BHRF1. We confirm that this is a direct, albeit weak, interaction via affinity pull-down assays and isothermal titration calorimetry. To understand the structural bases of BHRF1 specificity, we determined the 2.6 Å crystal structure of BHRF1 bound to the BID BH3D, which binds ∼400-times tighter to BHRF1 than does BECN1, and performed a detailed structural comparison with complexes of diverse BH3Ds bound to BHRF1 and to other antiapoptotic BCL2s. Lastly, we used mammalian cell autophagy assays to demonstrate that BHRF1 downregulates autophagy and that a cell-permeable peptide derived from the BID BH3D inhibits BHRF1-mediated downregulation of autophagy. In summary, our results suggest that BHRF1 downregulates autophagy by noncanonical binding of a flexible region of BECN1 that includes but is not limited to the BH3D and that BH3D-derived peptides that bind better to BHRF1 can block downregulation of autophagy by BHRF1.

PubMed: 37776275
DOI: 10.1021/acs.biochem.3c00225

Experimental method

X-RAY DIFFRACTION (2.61002612546 Å)