Role of the D1-D2 Linker of Human VCP/p97 in the Asymmetry and ATPase Activity of the D1-domain.
Tang, W.K., Xia, D.(2016) Sci Rep 6: 20037-20037
- PubMed: 26818443 
- DOI: https://doi.org/10.1038/srep20037
- Primary Citation of Related Structures:  
5DYG, 5DYI - PubMed Abstract: 
Human AAA(+) protein p97 consists of an N-domain and two tandem ATPase domains D1 and D2, which are connected by the N-D1 and the D1-D2 linkers. Inclusion of the D1-D2 linker, a 22-amino acid peptide, at the end of p97 N-D1 truncate has been shown to activate ATP hydrolysis of its D1-domain, although the mechanism of activation remains unclear. Here, we identify the N-terminal half of this linker, highly conserved from human to fungi, is essential for the ATPase activation. By analyzing available crystal structures, we observed that the D1-D2 linker is capable of inducing asymmetry in subunit association into a p97 hexamer. This observation is reinforced by two new crystal structures, determined in the present work. The effect of D1-D2 linker on the ATPase activity of the D1-domain is correlated to the side-chain conformation of residue R359, a trans-acting arginine-finger residue essential for ATP hydrolysis of the D1-domain. The activation in D1-domain ATPase activity by breaking perfect six-fold symmetry implies functional importance of asymmetric association of p97 subunits, the extent of which can be determined quantitatively by the metric Asymmetric Index.
Organizational Affiliation: 
Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.