Crystal structure of vesicular stomatitis virus matrix protein

The vesicular stomatitis virus (VSV) matrix protein (M) interacts with cellular membranes, self‐associates and plays a major role in virus assembly and budding. We present the crystallographic structure, determined at 1.96 Å resolution, of a soluble thermolysin resistant core of VSV M. The fold is a new fold shared by the other vesiculovirus matrix proteins. The structure accounts for the loss of stability of M temperature‐sensitive mutants deficient in budding, and reveals a flexible loop protruding from the globular core that is important for self‐assembly. Membrane floatation shows that, together with the M lysine‐rich N‐terminal peptide, a second domain of the protein is involved in membrane binding. Indeed, the structure reveals a hydrophobic surface located close to the hydrophobic loop and surrounded by conserved basic residues that may constitute this domain. Lastly, comparison of the negative‐stranded virus matrix proteins with retrovirus Gag proteins suggests that the flexible link between their major membrane binding domain and the rest of the structure is a common feature shared by these proteins involved in budding and virus assembly.