Structure and biochemical function of a prototypical Arabidopsis U-box domain

79Citations
Citations of this article
71Readers
Mendeley users who have this article in their library.

This article is free to access.

Abstract

U-box proteins, as well as other proteins involved in regulated protein degradation, are apparently over-represented in Arabidopsis compared with other model eukaryotes. The Arabidopsis protein AtPUB14 contains a typical U-box domain followed by an Armadillo repeat region, a domain organization that is frequently found in plant U-box proteins. In vitro ubiquitination assays demonstrated that AtPUB14 functions as an E3 ubiquitin ligase with specific E2 ubiquitin-conjugating enzymes. The structure of the AtPUB14 U-box domain was determined by NMR spectroscopy. It adopts the ββαβ fold of the Prp19p U-box and RING finger domains. In these proteins, conserved hydrophobic residues form a putative E2-binding cleft. By contrast, they contain no common polar E2 binding site motif. Two hydrophobic cores stabilize the AtPUB14 U-box fold, and hydrogen bonds and salt bridges interconnect the residues corresponding to zinc ion-coordinating residues in RING domains. Residues from a C-terminal α-helix interact with the core domain and contribute to stabilization. The Prpl9p U-box lacks a corresponding C-terminal α-helix. Chemical shift analysis suggested that aromatic residues exposed at the N terminus and the C-terminal α-helix of the AtPUB14 U-box participate in dimerization. Thus, AtPUB14 may form a biologically relevant dimer. This is the first plant U-box structure to be determined, and it provides a model for studies of the many plant U-box proteins and their interactions. Structural insight into these interactions is important, because ubiquitin-dependent protein degradation is a prevalent regulatory mechanism in plants.

Cite

CITATION STYLE

APA

Andersen, P., Kragelund, B. B., Olsen, A. N., Larsen, F. H., Chua, N. H., Poulsen, F. M., & Skriver, K. (2004). Structure and biochemical function of a prototypical Arabidopsis U-box domain. Journal of Biological Chemistry, 279(38), 40053–40061. https://doi.org/10.1074/jbc.M405057200

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free