Solution NMR structure of the TRIM21 B-box2 and identification of residues involved in its interaction with the RING domain.
 

Solution NMR structure of the TRIM21 B-box2 and identification of residues involved in its interaction with the RING domain.

Solution NMR structure of the TRIM21 B-box2 and identification of residues involved in its interaction with the RING domain.

PLoS One. 2017;12(7):e0181551

Authors: Wallenhammar A, Anandapadamanaban M, Lemak A, Mirabello C, Lundström P, Wallner B, Sunnerhagen M

Abstract
Tripartite motif-containing (TRIM) proteins are defined by the sequential arrangement of RING, B-box and coiled-coil domains (RBCC), where the B-box domain is a unique feature of the TRIM protein family. TRIM21 is an E3 ubiquitin-protein ligase implicated in innate immune signaling by acting as an autoantigen and by modifying interferon regulatory factors. Here we report the three-dimensional solution structure of the TRIM21 B-box2 domain by nuclear magnetic resonance (NMR) spectroscopy. The structure of the B-box2 domain, comprising TRIM21 residues 86-130, consists of a short ?-helical segment with an N-terminal short ?-strand and two anti-parallel ?-strands jointly found the core, and adopts a RING-like fold. This ???? core largely defines the overall fold of the TRIM21 B-box2 and the coordination of one Zn2+ ion stabilizes the tertiary structure of the protein. Using NMR titration experiments, we have identified an exposed interaction surface, a novel interaction patch where the B-box2 is likely to bind the N-terminal RING domain. Our structure together with comparisons with other TRIM B-box domains jointly reveal how its different surfaces are employed for various modular interactions, and provides extended understanding of how this domain relates to flanking domains in TRIM proteins.


PMID: 28753623 [PubMed - in process]



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