Solution structure of the small dictyostelium discoideium myosin light chain mlcb provides insights into iq-motif recognition of class i myosin myo1b

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 21 
  • Selection Criteria: structures with the lowest energy 

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Structure of the small Dictyostelium discoideum myosin light chain MlcB provides insights into MyoB IQ motif recognition.

Liburd, J.Chitayat, S.Crawley, S.W.Munro, K.Miller, E.Denis, C.M.Spencer, H.L.Cote, G.P.Smith, S.P.

(2014) J Biol Chem 289: 17030-17042

  • DOI: https://doi.org/10.1074/jbc.M113.536532
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Dictyostelium discoideum MyoB is a class I myosin involved in the formation and retraction of membrane projections, cortical tension generation, membrane recycling, and phagosome maturation. The MyoB-specific, single-lobe EF-hand light chain MlcB binds the sole IQ motif of MyoB with submicromolar affinity in the absence and presence of Ca(2+). However, the structural features of this novel myosin light chain and its interaction with its cognate IQ motif remain uncharacterized. Here, we describe the NMR-derived solution structure of apoMlcB, which displays a globular four-helix bundle. Helix 1 adopts a unique orientation when compared with the apo states of the EF-hand calcium-binding proteins calmodulin, S100B, and calbindin D9k. NMR-based chemical shift perturbation mapping identified a hydrophobic MyoB IQ binding surface that involves amino acid residues in helices I and IV and the functional N-terminal Ca(2+) binding loop, a site that appears to be maintained when MlcB adopts the holo state. Complementary mutagenesis and binding studies indicated that residues Ile-701, Phe-705, and Trp-708 of the MyoB IQ motif are critical for recognition of MlcB, which together allowed the generation of a structural model of the apoMlcB-MyoB IQ complex. We conclude that the mode of IQ motif recognition by the novel single-lobe MlcB differs considerably from that of stereotypical bilobal light chains such as calmodulin.

  • Organizational Affiliation

    From the Department of Biomedical and Molecular Sciences and.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
myosin light chain MlcB93Saccharomyces cerevisiaeMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 21 
  • Selection Criteria: structures with the lowest energy 

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-12-11
    Type: Initial release
  • Version 1.1: 2015-02-18
    Changes: Database references
  • Version 1.2: 2023-06-14
    Changes: Data collection, Database references, Other
  • Version 1.3: 2024-05-15
    Changes: Data collection, Database references