Crystal structure analysis of HIV-1 protease by complementary use of synchrotron radiation and neutron

Adachi, Motoyasu; Ohara, Takashi   ; Kurihara, Kazuo; Tamada, Taro; Honjo, Eijiro*; Okazaki, Nobuo; Arai, Shigeki; Shoyama, Yoshinari*; Matsumura, Hiroyoshi*; Sugiyama, Shigeru*; Adachi, Hiroaki*; Takano, Kazufumi*; Mori, Yusuke*; Hidaka, Koshi*; Kimura, Toru*; Hayashi, Yoshio*; Kiso, Yoshiaki*; Kuroki, Ryota

In this study, we determined crystal structures of HIV-1 protease complexed with inhibitor by neutron and X-ray crystallography. Finally, we refined the structures to R-factor of 17.3% and free R-factor 20.3% by neutron crystallography and to R-factor of 10.4 % and free R-factor 12.4% by X-ray crystallography. The result shows that Asp 25 residue is protonated and Asp 125 is deprotonated. These information is important to resolve catalytic mechanism and design of new potent inhibitor.