9KZ4 | pdb_00009kz4

Dihydrofolate reductase binding to NADPH and trimethoprim-tetramethylrhodamine


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.71 Å
  • R-Value Free: 
    0.196 (Depositor), 0.197 (DCC) 
  • R-Value Work: 
    0.171 (Depositor), 0.177 (DCC) 

Starting Model: experimental
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wwPDB Validation 3D Report Full Report

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Ligand Structure Quality Assessment 


This is version 1.1 of the entry. See complete history

Literature

Dynamic conformations of fluorophores on self-labeling protein tags.

Zhang, K.Zhang, J.Chen, N.Chen, Z.

(2026) Biophys J 

  • DOI: https://doi.org/10.1016/j.bpj.2026.06.033
  • Primary Citation Related Structures: 
    21DT, 9KZ4

  • PubMed Abstract: 

    Self-labeling protein tags (SLPs) enable protein-specific conjugation of synthetic fluorophores for versatile bioimaging, yet their rational engineering has largely relied on static structural models. Here, we reveal that crystal structures of SLP-dye complexes generally bear packing artifacts due to strong π-π interactions of dyes, frequently failing to profile the chromophore microenvironment. By integrating molecular dynamics (MD) with crystallography, we elucidate distinct dynamic behaviors of fluorophores across major SLPs: quasi-free diffusion in SNAP-tag, balanced hydrophobic-polar interactions in TMP-tag, and discrete, state-selective anchoring in HaloTag and Rho-tag. Comparisons with the newly developed SNAP-tag2 demonstrate that functional evolution reshapes conformational landscapes rather than merely strengthening binding. We further validate simulation-derived predictions through MD-guided lattice selection. Together, this work establishes a comparative, dynamic framework for understanding SLP-dye interactions beyond crystallography, while providing a conceptual basis for further engineering chemigenetic tools for advanced imaging and sensing.


  • Organizational Affiliation
    • College of Future Technology, Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing, 100871, China; Peking-Tsinghua Center for Life Science, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China. Electronic address: kechengzhang1234@163.com.

Macromolecule Content 

  • Total Structure Weight: 39.1 kDa 
  • Atom Count: 2,940 
  • Modeled Residue Count: 318 
  • Deposited Residue Count: 318 
  • Unique protein chains: 1

Macromolecules

Find similar proteins by:|  3D Structure
Entity ID: 1
MoleculeChains  Sequence LengthOrganismDetailsImage
Dihydrofolate reductaseA [auth B],
B [auth A]
159Escherichia coli K-12Mutation(s): 0 
Gene Names: folAtmrAb0048JW0047
EC: 1.5.1.3
UniProt
Find proteins for P0ABQ4 (Escherichia coli (strain K12))
Explore P0ABQ4 
Go to UniProtKB:  P0ABQ4
Entity Groups
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0ABQ4
Sequence Annotations
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Reference Sequence

Small Molecules

Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
NDP

Query on NDP



Download:Ideal Coordinates CCD File
C [auth B],
H [auth A]
NADPH DIHYDRO-NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE
C21 H30 N7 O17 P3
ACFIXJIJDZMPPO-NNYOXOHSSA-N
A1EHX

Query on A1EHX



Download:Ideal Coordinates CCD File
D [auth B],
I [auth A]
[9-[5-[2-[4-[[2,4-bis(azanyl)pyrimidin-5-yl]methyl]-2,6-dimethoxy-phenoxy]ethylcarbamoyl]-2-carboxy-phenyl]-6-(dimethylamino)xanthen-3-ylidene]-dimethyl-azanium
C40 H42 N7 O7
JYRINKWAGFHPTL-UHFFFAOYSA-O
MG

Query on MG



Download:Ideal Coordinates CCD File
E [auth B]
F [auth B]
G [auth B]
J [auth A]
K [auth A]
E [auth B],
F [auth B],
G [auth B],
J [auth A],
K [auth A],
L [auth A],
M [auth A]
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.71 Å
  • R-Value Free:  0.196 (Depositor), 0.197 (DCC) 
  • R-Value Work:  0.171 (Depositor), 0.177 (DCC) 
Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 79.995α = 90
b = 79.995β = 90
c = 106.073γ = 120
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling
PHENIXphasing

Structure Validation

View Full Validation Report



Ligand Structure Quality Assessment 


Entry History 

& Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Chinese Scholarship CouncilChina31971375

Revision History  (Full details and data files)

  • Version 1.0: 2025-01-22
    Type: Initial release
  • Version 1.1: 2026-07-08
    Changes: Database references