Abstact

In the face of increasing drug resistance and the rapidly increasing necessity for practicality in clinical settings, drugs targeting different viral proteins are needed in order to control influenza A and B. A small molecule that tenaciously adheres to the PB2cap binding domain, part of the heterotrimeric RNA polymerase machinery of influenza A virus and influenza B virus, is a promising drug candidate. Understanding the anatomic behavior of PB2cap upon ligand binding will aid in the development of a more robust inhibitor. In this report, the anatomic behavior of the influenza A virus PB2cap domain is established by solving the crystal structure of native influenza A virus PB2cap at 1.52 Å resolution. By comparing it with the ligand-bound structure, the dissociation and rotation of the ligand-binding domain in PB2cap from the C-terminal domain is identified. This domain movement is present in many PB2cap structures, suggesting its functional relevance for polymerase activity.