Drosophila melanogaster UNC89 Protein Kinase 1 in complex with ADP

Experimental Data Snapshot

  • Resolution: 1.90 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.173 
  • R-Value Observed: 0.175 

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This is version 1.2 of the entry. See complete history


PK1 from Drosophila obscurin is an inactive pseudokinase with scaffolding properties.

Zacharchenko, T.Dorendorf, T.Locker, N.Van Dijk, E.Katzemich, A.Diederichs, K.Bullard, B.Mayans, O.

(2023) Open Biol 13: 220350-220350

  • DOI: https://doi.org/10.1098/rsob.220350
  • Primary Citation of Related Structures:  
    8AK2, 8AK3

  • PubMed Abstract: 

    Obscurins are large filamentous proteins with crucial roles in the assembly, stability and regulation of muscle. Characteristic of these proteins is a tandem of two C-terminal kinase domains, PK1 and PK2, that are separated by a long intrinsically disordered sequence. The significance of this conserved domain arrangement is unknown. Our study of PK1 from Drosophila obscurin shows that this is a pseudokinase with features typical of the CAM-kinase family, but which carries a minimalistic regulatory tail that no longer binds calmodulin or has mechanosensory properties typical of other sarcomeric kinases. PK1 binds ATP with high affinity, but in the absence of magnesium and lacks detectable phosphotransfer activity. It also has a highly diverged active site, strictly conserved across arthropods, that might have evolved to accommodate an unconventional binder. We find that PK1 interacts with PK2, suggesting a functional relation to the latter. These findings lead us to speculate that PK1/PK2 form a pseudokinase/kinase dual system, where PK1 might act as an allosteric regulator of PK2 and where mechanosensing properties, akin to those described for regulatory tails in titin-like kinases, might now reside on the unstructured interkinase segment. We propose that the PK1-interkinase-PK2 region constitutes an integrated functional unit in obscurin proteins.

  • Organizational Affiliation

    Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Obscurin297Drosophila melanogasterMutation(s): 0 
Gene Names: Unc-89CG33519
Find proteins for A8DYP0 (Drosophila melanogaster)
Explore A8DYP0 
Go to UniProtKB:  A8DYP0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA8DYP0
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.90 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.173 
  • R-Value Observed: 0.175 
  • Space Group: P 63 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 95.418α = 90
b = 95.418β = 90
c = 164.6γ = 120
Software Package:
Software NamePurpose
Cootmodel building
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Human Frontier Science Program (HFSP)FranceRGP0044/2012

Revision History  (Full details and data files)

  • Version 1.0: 2023-03-29
    Type: Initial release
  • Version 1.1: 2023-05-10
    Changes: Database references
  • Version 1.2: 2024-02-07
    Changes: Data collection, Refinement description