9MRX | pdb_00009mrx

Cryo-EM structure of KwaA-KwaB complex

• PDB DOI: https://doi.org/10.2210/pdb9MRX/pdb
• EM Map EMD-48564: EMDB EMDataResource

• Classification: IMMUNE SYSTEM
• Organism(s): Escherichia coli
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2025-01-08 Released: 2025-08-06 
• Deposition Author(s): Zhang, Z., Patel, D.J.
• Funding Organization(s): National Institutes of Health/National Cancer Institute (NIH/NCI)

---

Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 3.75 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Literature

Cryo-EM structure of KwaA-KwaB complex

Zhang, Z., Patel, D.J.

To be published.

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 11-mer - A7B4 

Local Symmetry: Cyclic - C4  (Explore in 3D)
Local Stoichiometry: Homo 4-mer - B4 Local Symmetry: Cyclic - C2  (Explore in 3D)
Local Stoichiometry: Homo 2-mer - A2 Local Symmetry: Cyclic - C2  (Explore in 3D)
Local Stoichiometry: Homo 2-mer - A2 Local Symmetry: Cyclic - C2  (Explore in 3D)
Local Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors.

Biological Assembly Evidence: electron microscopy

Macromolecule Content 

• Total Structure Weight: 343.14 kDa 
• Atom Count: 24,165 
• Modeled Residue Count: 2,985 
• Deposited Residue Count: 2,985 
• Unique protein chains: 2

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Kiwa protein KwaA	A [auth G], B [auth A], C, D [auth I]	195	Escherichia coli	Mutation(s): 0  Gene Names: kwaA, ECO55CA74_24535
UniProt
Find proteins for P0DW45 (Escherichia coli O55:H7 (strain RM12579 / EPEC)) Explore P0DW45  Go to UniProtKB:  P0DW45

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Kiwa protein KwaB	E [auth K], F [auth L], G [auth H], H [auth J], I [auth D], J [auth E], K [auth F]	315	Escherichia coli	Mutation(s): 0  Gene Names: kwaB, ECO55CA74_24530
UniProt
Find proteins for P0DW46 (Escherichia coli O55:H7 (strain RM12579 / EPEC)) Explore P0DW46  Go to UniProtKB:  P0DW46

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 3.75 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

EM Software:

Task	Software Package	Version
MODEL REFINEMENT	PHENIX	1.20.1_4487

Structure Validation

Entry History & Funding Information

Deposition Data

• Released Date: 2025-08-06 
Deposition Author(s): Zhang, Z., Patel, D.J.

---

Funding Organization	Location	Grant Number
National Institutes of Health/National Cancer Institute (NIH/NCI)	United States	P30 CA008748

Revision History  

• Version 1.0: 2025-08-06
  Type: Initial release