title: Detailed structural insights into the p97-Npl4-Ufd1 interface.
abstract: The AAA ATPase, p97, achieves its versatility through binding to a wide range of cofactor proteins that adapt it to different cellular functions. The heterodimer UN (comprising Ufd1 and Npl4) is an adaptor complex that recruits p97 for numerous tasks, many of which involve the ubiquitin pathway. Insights into the structural specificity of p97 for its UN adaptor are currently negligible. Here, we present the solution structure of the Npl4 "ubiquitin-like" domain (UBD), which adopts a beta-grasp fold with a 3(10) helical insert. Moreover we performed a chemical shift perturbation analysis of its binding surface with the p97 N domain. We assigned the backbone amides of the p97 N domain and probed both its reciprocal binding surface with Npl4 UBD and its interaction with the p97-binding region of Ufd1. NMR data recorded on a 400-kDa full-length UN-hexamer p97 complex reveals an identical mode of interaction. We calculated a structural model for the p97 N-Npl4 UBD complex, and a comparison with the p97-p47 adaptor complex reveals subtle differences in p97 adaptor recognition and specificity.
authors.affiliation: Division of Molecular Biosciences, Imperial College London, Biochemistry Building, South Kensington, London SW7 2AZ, United Kingdom.
authors.forename: Rivka L
authors.initials: RL
authors.lastname: Isaacson
authors.forename: Valerie E
authors.initials: VE
authors.lastname: Pye
authors.forename: Peter
authors.initials: P
authors.lastname: Simpson
authors.forename: Hemmo H
authors.initials: HH
authors.lastname: Meyer
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zhang
authors.forename: Paul S
authors.initials: PS
authors.lastname: Freemont
authors.forename: Steve
authors.initials: S
authors.lastname: Matthews
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000502:physiology*; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000502:physiology*
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; C506084:Npl4 protein, mouse; D009687:Nuclear Proteins; D011506:Proteins; C107396:Ufd1 protein, mouse; D000251:Adenosine Triphosphatases; C404942:p97 ATPase