Solution structure and interaction surface of the C-terminal domain from p47: A major p97-cofactor involved in SNARE disassembly

p47 is the major protein identified in complex with the cytosolic AAA ATPas e p97. It functions as an essential cofactor of p97-regulated membrane fusi on, which has been suggested to disassemble t-t-SNARE complexes and prepare them for further rounds of membrane fusion. Here, we report the high-resol ution NMR structure of the C-terminal domain from p47. It comprises a UBX d omain and a 13 residue long structured N-terminal extension. The UBX domain adopts a characteristic ubiquitin fold with a beta beta alpha beta beta al pha beta secondary structure arrangement. Three hydrophobic residues from t he N-terminal extension pack closely against a cleft in the UBX domain. We also identify, for the first time, the p97 interaction surface using NMR ch emical shift perturbation studies. (C) 2001 Academic Press.