45PC: Dihydrofolate reductase

6-conformation model of Escherichia coli dihydrofolate reductase at 100K. Determined by X-ray diffraction at 0.85 Å resolution. Released 30 Sept 2026.

Method: X-ray diffraction
Resolution: 0.85 Å
Organism: Escherichia coli str. K-12 substr. MC4100
Chains: 1
Atoms: 10,753
Mol. weight: 19.38 kDa
Ligands: FOL, NAP, MN
Released: 30 Sept 2026

Explore 45PC in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

45PC contains 6 α-helices and 12 β-strands across 1 chain. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain A: 6 helices, 12 β-strands

Element	Residues	Length	Sheet
β-strand	2-8	7	1
α-helix	10-12	3
β-strand	13-15	3	2
β-strand	16	1	3
β-strand	19	1	3
α-helix	25-35	11
β-strand	40-43	4	1
α-helix	44-50	7
β-strand	59-62	4	1
β-strand	73-75	3	1
α-helix	78-85	8
β-strand	91-93	3	1
α-helix	97-103	7
β-strand	109-115	7	1
β-strand	123-124	2	2
α-helix	130-132	3
β-strand	133-141	9	1
β-strand	151-158	8	1

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Dihydrofolate reductase	A	protein	159	Escherichia coli str. K-12 substr. MC4100	P0ABQ4 (AlphaFold model)

Sequence of entity 1 (A), FASTA

>45PC_1 Dihydrofolate reductase (chains A)
MISLIAALAVDRVIGMENAMPWNLPADLAWFKRNTLNKPVIMGRHTWESIGRPLPGRKNI
ILSSQPGTDDRVTWVKSVDEAIAACGDVPEIMVIGGGRVYEQFLPKAQKLYLTHIDAEVE
GDTHFPDYEPDDWESVFSEFHDADAQNSHSYCFEILERR

Ligands and cofactors

ID	Name	Formula	Copies
FOL	Folic acid	C19 H19 N7 O6	1
NAP	NADP nicotinamide-adenine-dinucleotide phosphate	C21 H28 N7 O17 P3	1
MN	Manganese (II) ion	Mn	2

Water and common crystallization additives (CL) are not listed.

Primary citation

Optimizing the connectivity of protein conformations to untangle ensemble refinement. Passmore, S.K., Holton, J.M., Zatsepin, N.A. et al. bioRxiv (2026). DOI 10.64898/2026.09.17.752399

Other PDB entries of the same protein (UniProt P0ABQ4 (AlphaFold model), which also has an AlphaFold model), best resolution first:

9PWM 0.89 Å, Dihydrofolate Reductase Complexed with Folate and Nicotinamide Adenine Dinucleotide…
8UW0 0.93 Å, Escherichia coli DHFR bound to NADP+ and folate, 17.2 MGy dose
6CW7 1.03 Å, E. coli DHFR product complex with (6S)-5,6,7,8-TETRAHYDROFOLATE
7FPP 1.03 Å, DHFR:NADP+:FOL complex at 280 K (crystal 5)
7FPQ 1.03 Å, DHFR:NADP+:FOL complex at 280 K (multi-crystal)
7FPM 1.04 Å, DHFR:NADP+:FOL complex at 280 K (crystal 2)
7FPN 1.04 Å, DHFR:NADP+:FOL complex at 280 K (crystal 3)
7FPV 1.04 Å, DHFR:NADP+:FOL complex at 290 K (crystal 5)
7FPW 1.04 Å, DHFR:NADP+:FOL complex at 290 K (multi-crystal)
7FPU 1.05 Å, DHFR:NADP+:FOL complex at 290 K (crystal 4)
5SSW 1.06 Å, DHFR:NADP+:FOL complex at 270 K (multi-crystal)
7FPO 1.06 Å, DHFR:NADP+:FOL complex at 280 K (crystal 4)

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