Human Brr2 Helicase Region M641C/A1582C

Experimental Data Snapshot

  • Resolution: 3.17 Å
  • R-Value Free: 0.318 
  • R-Value Work: 0.264 
  • R-Value Observed: 0.267 

Starting Model: experimental
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The inactive C-terminal cassette of the dual-cassette RNA helicase BRR2 both stimulates and inhibits the activity of the N-terminal helicase unit.

Vester, K.Santos, K.F.Kuropka, B.Weise, C.Wahl, M.C.

(2020) J Biol Chem 295: 2097-2112

  • DOI: https://doi.org/10.1074/jbc.RA119.010964
  • Primary Citation of Related Structures:  
    6S8O, 6S8Q, 6S9I

  • PubMed Abstract: 

    The RNA helicase bad response to refrigeration 2 homolog (BRR2) is required for the activation of the spliceosome before the first catalytic step of RNA splicing. BRR2 represents a distinct subgroup of Ski2-like nucleic acid helicases whose members comprise tandem helicase cassettes. Only the N-terminal cassette of BRR2 is an active ATPase and can unwind substrate RNAs. The C-terminal cassette represents a pseudoenzyme that can stimulate RNA-related activities of the N-terminal cassette. However, the molecular mechanisms by which the C-terminal cassette modulates the activities of the N-terminal unit remain elusive. Here, we show that N- and C-terminal cassettes adopt vastly different relative orientations in a crystal structure of BRR2 in complex with an activating domain of the spliceosomal Prp8 protein at 2.4 Å resolution compared with the crystal structure of BRR2 alone. Likewise, inspection of BRR2 structures within spliceosomal complexes revealed that the cassettes occupy different relative positions and engage in different intercassette contacts during different splicing stages. Engineered disulfide bridges that locked the cassettes in two different relative orientations had opposite effects on the RNA-unwinding activity of the N-terminal cassette, with one configuration enhancing and the other configuration inhibiting RNA unwinding compared with the unconstrained protein. Moreover, we found that differences in relative positioning of the cassettes strongly influence RNA-stimulated ATP hydrolysis by the N-terminal cassette. Our results indicate that the inactive C-terminal cassette of BRR2 can both positively and negatively affect the activity of the N-terminal helicase unit from a distance.

  • Organizational Affiliation

    Structural Biochemistry Group, Department of Biochemistry, Freie Universität Berlin, Takustrasse 63, D-14195 Berlin, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
U5 small nuclear ribonucleoprotein 200 kDa helicaseA [auth B]1,747Homo sapiensMutation(s): 2 
UniProt & NIH Common Fund Data Resources
Find proteins for O75643 (Homo sapiens)
Explore O75643 
Go to UniProtKB:  O75643
GTEx:  ENSG00000144028 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO75643
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 3.17 Å
  • R-Value Free: 0.318 
  • R-Value Work: 0.264 
  • R-Value Observed: 0.267 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 145.564α = 90
b = 152.531β = 120.69
c = 142.515γ = 90
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
German Research FoundationGermanyTRR186

Revision History  (Full details and data files)

  • Version 1.0: 2020-01-22
    Type: Initial release
  • Version 1.1: 2020-02-26
    Changes: Database references
  • Version 1.2: 2024-01-24
    Changes: Data collection, Database references, Refinement description