Crystal Structures of N-terminal Domain of Human Hsp90 With ATP Analogues Reveal The Functional Regulation of Hsp90*: Crystal Structures of N-terminal Domain of Human Hsp90 With ATP Analogues Reveal The Functional Regulation of Hsp90*

Heat shock protein 90 (Hsp90) is essential for folding, maturation and stabilization of many important proteins, which are involved in cell cycle regulation, signal transduction, and cell growth regulation. The highly conserved N-terminal domain contains an ATP binding cleft and thus is responsible for the catalytic activity of Hsp90. In order to further study the function and structure of Hsp90, the N-terminal of the human Hsp90 was cocrystallized with AMPPNP and ATP gamma S. The cocrystallization experiments were carried out at 277K using the hanging drop vapor-diffusion method, X-ray diffraction data were collected on beamline 17U at the SSRF and the structures were solved by molecular replacement. The densities of the two nucleotides were captured and the interactions between Hsp90(N) and nucleotides were clearly described. We confirmed that the gamma-phosphate of ATP gamma S was not hydrolyzed by Hsp90(N). The position of S 1 and ATP lid in human Hsp90(N)-AMPPNP differs significantly from that of the structure of yeast Hsp90-AMPPNP. By analyzing the structure of human Hsp90(N)-AMPPNP, we found that the interactions of E18-K100 and N40-D127 block the moving of Si and ATP lid, and then prevent the dimerization of Hsp90(N). This reflects the complexity and coordination of Hsp90 on the regulation of the function.