Crystal structure of TNFα complexed with a poxvirus MHC-related TNF binding protein

Abstract

The poxvirus 2L protein binds tumor necrosis factor-α (TNFα). Structural data now indicate that 2L interacts with TNFα at a site overlapping with that for its receptor, arguing for the basis of inhibition of receptor interaction and TNFα-induced immune responses. The poxvirus 2L protein binds tumor necrosis factor-α (TNFα) to inhibit host antiviral and immune responses. The 2.8-Å 2L–TNFα structure reveals three symmetrically arranged 2L molecules per TNFα trimer. 2L resembles class I major histocompatibility complex (MHC) molecules but lacks a peptide-binding groove and β2-microglobulin light chain. Overlap between the 2L and host TNF receptor-binding sites on TNFα rationalizes 2L inhibition of TNFα–TNF receptor interactions and prevention of TNFα-induced immune responses.