Structure of the Human Mitogen-Activated Protein Kinase Kinase 1 (MEK1)

Experimental Data Snapshot

  • Resolution: 2.20 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.201 

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Structure of mitogen-activated protein kinase kinase 1 in the DFG-out conformation.

Nakae, S.Kitamura, M.Fujiwara, D.Sawa, M.Shirai, T.Fujii, I.Tada, T.

(2021) Acta Crystallogr F Struct Biol Commun 77: 459-464

  • DOI: https://doi.org/10.1107/S2053230X21011687
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Eukaryotic protein kinases contain an Asp-Phe-Gly (DFG) motif, the conformation of which is involved in controlling the catalytic activity, at the N-terminus of the activation segment. The motif can be switched between active-state (DFG-in) and inactive-state (DFG-out) conformations: however, the mechanism of conformational change is poorly understood, partly because there are few reports of the DFG-out conformation. Here, a novel crystal structure of nonphosphorylated human mitogen-activated protein kinase kinase 1 (MEK1; amino acids 38-381) complexed with ATP-γS is reported in which MEK1 adopts the DFG-out conformation. The crystal structure revealed that the structural elements (the αC helix and HRD motif) surrounding the active site are involved in the formation/stabilization of the DFG-out conformation. The ATP-γS molecule was bound to the canonical ATP-binding site in a different binding mode that has never been found in previously determined crystal structures of MEK1. This novel ATP-γS binding mode provides a starting point for the design of high-affinity inhibitors of nonphosphorylated inactive MEK1 that adopts the DFG-out conformation.

  • Organizational Affiliation

    Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Dual specificity mitogen-activated protein kinase kinase 1350Homo sapiensMutation(s): 2 
Gene Names: MAP2K1MEK1PRKMK1
UniProt & NIH Common Fund Data Resources
Find proteins for Q02750 (Homo sapiens)
Explore Q02750 
Go to UniProtKB:  Q02750
PHAROS:  Q02750
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ02750
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on AGS

Download Ideal Coordinates CCD File 
C10 H16 N5 O12 P3 S
Experimental Data & Validation

Experimental Data

  • Resolution: 2.20 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.201 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 47.815α = 90
b = 96.191β = 90
c = 138.617γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-03-26
    Type: Initial release
  • Version 1.1: 2021-12-22
    Changes: Database references, Derived calculations