9UW4 | pdb_00009uw4

The complex of human pMEK1 and uERK1 (ANP)(from pY204ERK1)

• PDB DOI: https://doi.org/10.2210/pdb9UW4/pdb
• EM Map EMD-64545: EMDB EMDataResource

• Classification: TRANSFERASE
• Organism(s): Homo sapiens
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2025-05-12 Released: 2026-04-01 
• Deposition Author(s): Peng, C., Sun, Y., Liu, S., Zhou, F., Hu, Q.
• Funding Organization(s): Other government

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Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 3.20 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Starting Model: in silico

Literature

Mechanistic insight into the phosphorylation of ERK by MEK

Sun, Y., Peng, C., Liu, S., Zhou, F., Huang, G., Wang, J., Hu, Q.

(2026) bioRxiv 

• DOI: https://doi.org/10.64898/2026.03.13.710243

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 2-mer - A1B1 Pseudo Symmetry: Cyclic - C2  (Explore in 3D)
Pseudo Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors.

Biological Assembly Evidence: electron microscopy

Macromolecule Content 

• Total Structure Weight: 90.44 kDa 
• Atom Count: 5,269 
• Modeled Residue Count: 652 
• Deposited Residue Count: 791 
• Unique protein chains: 2

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Mitogen-activated protein kinase 3	A [auth B]	388	Homo sapiens	Mutation(s): 0  Gene Names: MAPK3, ERK1, PRKM3 EC: 2.7.11.24
UniProt & NIH Common Fund Data Resources
Find proteins for P27361 (Homo sapiens) Explore P27361  Go to UniProtKB:  P27361
PHAROS:  P27361 GTEx:  ENSG00000102882

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Dual specificity mitogen-activated protein kinase kinase 1	B [auth A]	403	Homo sapiens	Mutation(s): 0  Gene Names: MAP2K1, MEK1, PRKMK1 EC: 2.7.12.2
UniProt & NIH Common Fund Data Resources
Find proteins for Q02750 (Homo sapiens) Explore Q02750  Go to UniProtKB:  Q02750
PHAROS:  Q02750 GTEx:  ENSG00000169032

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
ANP (Subject of Investigation/LOI)	D [auth B], E [auth A]	PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER C10 H17 N6 O12 P3 PVKSNHVPLWYQGJ-KQYNXXCUSA-N
MG (Subject of Investigation/LOI)	C [auth B]	MAGNESIUM ION Mg JLVVSXFLKOJNIY-UHFFFAOYSA-N

Modified Residues  1 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
SEP	B [auth A]	L-PEPTIDE LINKING	C3 H8 N O6 P		SER

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 3.20 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

EM Software:

Task	Software Package	Version
MODEL REFINEMENT	PHENIX
MODEL REFINEMENT	Coot
MODEL REFINEMENT	UCSF ChimeraX

Structure Validation

Entry History & Funding Information

Deposition Data

• Released Date: 2026-04-01 
Deposition Author(s): Peng, C., Sun, Y., Liu, S., Zhou, F., Hu, Q.

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Funding Organization	Location	Grant Number
Other government	China	2023C03109

Revision History  

• Version 1.0: 2026-04-01
  Type: Initial release