FBP21's C-Terminal Domain Remains Dynamic When Wrapped around the c-Sec63 Unit of Brr2 Helicase

Jana Sticht; Miriam Bertazzon; Lisa M Henning; Jan R Licha; Esam T Abualrous; Christian Freund

doi:10.1016/j.bpj.2018.11.3123

FBP21's C-Terminal Domain Remains Dynamic When Wrapped around the c-Sec63 Unit of Brr2 Helicase

Biophys J. 2019 Feb 5;116(3):406-418. doi: 10.1016/j.bpj.2018.11.3123. Epub 2018 Nov 29.

Authors

Jana Sticht¹, Miriam Bertazzon², Lisa M Henning², Jan R Licha², Esam T Abualrous³, Christian Freund⁴

Affiliations

¹ Laboratory of Protein Biochemistry, Freie Universität Berlin, Berlin, Germany; Core Facility BioSupraMol, Freie Universität Berlin, Berlin, Germany. Electronic address: sticht@zedat.fu-berlin.de.
² Laboratory of Protein Biochemistry, Freie Universität Berlin, Berlin, Germany.
³ Laboratory of Protein Biochemistry, Freie Universität Berlin, Berlin, Germany; Computational Molecular Biology Group, Freie Universität Berlin, Berlin, Germany.
⁴ Laboratory of Protein Biochemistry, Freie Universität Berlin, Berlin, Germany. Electronic address: chfreund@zedat.fu-berlin.de.

Abstract

Based on our recent finding that FBP21 regulates human Brr2 helicase activity involved in the activation of the spliceosomal B-complex, we investigated the structural and dynamic contribution of FBP21 to the interaction. By using NMR spectroscopy, we could show that the 50 C-terminal residues of FBP21 (FBP21^326-376), which are sufficient to fully form the interaction with the C-terminal Sec63 unit of Brr2 (Brr2^C-Sec63), adopt a random-coil conformation in their unbound state. Upon interaction with Brr2^C-Sec63, 42 residues of FBP21^326-376 cover the large binding site on Brr2^C-Sec63 in an extended conformation. Short charged motifs are steering complex formation, still allowing the bound state to retain dynamics. Based on fragment docking in combination with experimental restraints, we present models of the complex structure. The FBP21^326-376/Brr2^C-Sec63 interaction thus presents an example of an intrinsically disordered protein/ordered-protein interaction in which a large binding site provides high specificity and, in combination with conformational disorder, displays a relatively high affinity.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Humans
Molecular Docking Simulation
Nuclear Proteins / chemistry*
Nuclear Proteins / metabolism*
Protein Domains
RNA-Binding Proteins / chemistry*
RNA-Binding Proteins / metabolism*
Ribonucleoproteins, Small Nuclear / chemistry*
Ribonucleoproteins, Small Nuclear / metabolism*
Thermodynamics

Substances

Nuclear Proteins
RNA-Binding Proteins
Ribonucleoproteins, Small Nuclear
SNRNP200 protein, human
WBP4 protein, human