9XZK | pdb_00009xzk

Cryo-EM structure of F-box helicase 1 (FBH1) bound to an SCF ubiquitin ligase complex and a 3-way DNA fork (head structure)

• PDB DOI: https://doi.org/10.2210/pdb9XZK/pdb
• EM Map EMD-72359: EMDB EMDataResource

• Classification: TRANSFERASE
• Organism(s): Homo sapiens
• Expression System: Spodoptera frugiperda
• Mutation(s): No 


• Deposited: 2025-08-27 Released: 2026-01-28 
• Deposition Author(s): Mullins, E.A., Schiltz, C.J., Eichman, B.F.
• Funding Organization(s): National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS), National Institutes of Health/National Cancer Institute (NIH/NCI)

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Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 3.91 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Starting Models: experimental, in silico

Literature

F-box helicase 1 reverses replication forks through assembly on the lagging strand template at the fork junction

Greer, B.H., Mendia Garcia, J., Mullins, E.A., Peacock, E.M., Haigh, S., Schiltz, C.J., Tsai, M.-S., Cortez, D., Moreno-Herrero, F., Eichman, B.F.

To be published.

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 2-mer - A1B1 

Biological assembly 1 assigned by authors.

Biological Assembly Evidence: electron microscopy

Macromolecule Content 

• Total Structure Weight: 102.09 kDa 
• Atom Count: 3,985 
• Modeled Residue Count: 492 
• Deposited Residue Count: 884 
• Unique protein chains: 2

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Cullin-1	A [auth C]	776	Homo sapiens	Mutation(s): 0  Gene Names: CUL1
UniProt & NIH Common Fund Data Resources
Find proteins for Q13616 (Homo sapiens) Explore Q13616  Go to UniProtKB:  Q13616
PHAROS:  Q13616 GTEx:  ENSG00000055130

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
E3 ubiquitin-protein ligase RBX1	B [auth R]	108	Homo sapiens	Mutation(s): 0  Gene Names: RBX1, RNF75, ROC1 EC: 2.3.2.27 (PDB Primary Data), 2.3.2.32 (PDB Primary Data)
UniProt & NIH Common Fund Data Resources
Find proteins for P62877 (Homo sapiens) Explore P62877  Go to UniProtKB:  P62877
PHAROS:  P62877 GTEx:  ENSG00000100387

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 3.91 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

EM Software:

Task	Software Package	Version
RECONSTRUCTION	RELION
MODEL REFINEMENT	Coot
MODEL REFINEMENT	PHENIX

Structure Validation

Entry History & Funding Information

Deposition Data

• Released Date: 2026-01-28 
Deposition Author(s): Mullins, E.A., Schiltz, C.J., Eichman, B.F.

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Funding Organization	Location	Grant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)	United States	R35 GM136401
National Institutes of Health/National Cancer Institute (NIH/NCI)	United States	P01 CA092584

Revision History  

• Version 1.0: 2026-01-28
  Type: Initial release