Conformational Changes of p97 during Nucleotide Hydrolysis Determined by Small-Angle X-Ray Scattering

• Published in: Structure (London) 2005-02, Vol.13 (2), p.183-195
• Main Authors: Davies, Jason M., Tsuruta, Hirotsugu, May, Andrew P., Weis, William I.
• Format: Article
• Language: English
• Subjects: Adenosine Triphosphatases; Adenosine Triphosphate - chemistry; Adenosine Triphosphate - metabolism; Cell Cycle Proteins - chemistry; Cell Cycle Proteins - metabolism; Hydrolysis; Models, Molecular; Protein Structure, Tertiary; Valosin Containing Protein; X-Ray Diffraction
• ISSN: 0969-2126; 1878-4186
• DOI: 10.1016/j.str.2004.11.014

Valosin-containing protein (VCP)/p97 is an AAA family ATPase that has been implicated in the removal of misfolded proteins from the endoplasmic reticulum and in membrane fusion. p97 forms a homohexamer whose protomers consist of an N-terminal (N) domain responsible for binding to effector proteins, followed by two AAA ATPase domains, D 1 and D 2. Small-angle X-ray scattering (SAXS) measurements of p97 in the presence of AMP-PNP (ATP state), ADP-AlF x (hydrolysis transition state), ADP, or no nucleotide reveal major changes in the positions of the N domains with respect to the hexameric ring during the ATP hydrolysis cycle. Nucleotide binding and hydrolysis experiments indicate that D 2 inhibits nucleotide exchange by D 1. The data suggest that the conversion of the chemical energy of ATP hydrolysis into mechanical work on substrates involves transmission of conformational changes generated by D 2 through D 1 to move N.