Structural basis for therapeutic inhibition of influenza A polymerase PB2 subunit per Xiaolei Ma, Lili Xie, Charles Wartchow, Robert Warne, Yongjin Xu, Alexey Rivkin, David Tully, Steven Shia, Kyoko Uehara, Dianna M. Baldwin, Gladys Muiru, Weidong Zhong, Isabel Zaror, Dirksen E. Bussiere, Vincent H. J. Leonard