9N3L: Co-crystal structure of PCNA

Co-crystal structure of PCNA bound to HSP90alpha inhibitor, SNX2112. Determined by X-ray diffraction at 1.9 Å resolution. Released 25 Feb 2026.

Method: X-ray diffraction
Resolution: 1.9 Å
Organism: Homo sapiens
Chains: 1
Atoms: 2,042
Mol. weight: 29.43 kDa
Ligands: E0G
Released: 25 Feb 2026

Explore 9N3L in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9N3L contains 9 α-helices and 19 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: 9 helices, 19 β-strands

Element	Residues	Length	Sheet
β-strand	2-6	5	1
α-helix	10-19	10
β-strand	25-31	7	2
β-strand	34-40	7	2
β-strand	46-53	8	2
α-helix	54-56	3
β-strand	59-62	4	1
β-strand	66-71	6	2
α-helix	72-79	8
β-strand	88-92	5	1
β-strand	98-103	6	1
β-strand	112-117	6	1
α-helix	118	1
β-strand	119	1	2
α-helix	127-130	4
β-strand	135-140	6	2
α-helix	141-151	11
β-strand	157-162	6	3
β-strand	166-173	8	3
β-strand	176-183	8	3
β-strand	196-199	4	2
β-strand	203-208	6	3
α-helix	209-215	7
α-helix	216-221	6
β-strand	224-229	6	2
β-strand	235-241	7	2
β-strand	245-251	7	2
α-helix	252-254	3

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Proliferating cell nuclear antigen	A	protein	261	Homo sapiens	P12004 (AlphaFold model)

Sequence of entity 1 (A), FASTA

>9N3L_1 Proliferating cell nuclear antigen (chains A)
MFEARLVQGSILKKVLEALKDLINEACWDISSSGVNLQSMDSSHVSLVQLTLRSEGFDTY
RCDRNLAMGVNLTSMSKILKCAGNEDIITLRAEDNADTLALVFEAPNQEKVSDYEMKLMD
LDVEQLGIPEQEYSCVVKMPSGEFARICRDLSHIGDAVVISCAKDGVKFSASGELGNGNI
KLSQTSNVDKEEEAVTIEMNEPVQLTFALRYLNFFTKATPLSSTVTLSMSADVPLVVEYK
IADMGHLKYYLAPKIEDEEGS

Ligands and cofactors

ID	Name	Formula	Copies
E0G	4-[6,6-dimethyl-4-oxidanylidene-3-(trifluoromethyl)-5,7-dihydroindazol-1-yl]-2-…	C23 H27 F3 N4 O3	1

Water and common crystallization additives (SO4, CL) are not listed.

Primary citation

Screening for novel chemical scaffolds targeting PCNA identifies the Hsp90alpha inhibitor SNX-2112. Jossart, J., Ma, N., Haratipour, P. et al. Curr Res Struct Biol (2026) 11:100183-100183. DOI 10.1016/j.crstbi.2026.100183 · PubMed

Other PDB entries of the same protein (UniProt P12004 (AlphaFold model), which also has an AlphaFold model), best resolution first:

1U7B 1.88 Å, Crystal structure of hPCNA bound to residues 331-350 of the flap endonuclease-1 (FEN1)
8F5Q 1.9 Å, Crystal structure of human PCNA in complex with the PIP box of FBH1
5E0U 1.93 Å, Human PCNA variant (S228I) complexed with p21 at 1.9 Angstroms
5MLO 1.96 Å, Crystal structure of human PCNA in complex with ZRANB3 PIP box peptide
4RJF 2.01 Å, Crystal structure of the human sliding clamp at 2.0 angstrom resolution
5E0V 2.07 Å, Human PCNA variant (S228I) complexed with FEN1 at 2.1 Angstroms
3VKX 2.1 Å, Structure of PCNA
6HVO 2.1 Å, Crystal structure of human PCNA in complex with three peptides of p12 subunit of human…
4ZTD 2.2 Å, Crystal Structure of Human PCNA in complex with a TRAIP peptide
5YCO 2.2 Å, Complex structure of PCNA with UHRF2
5MOM 2.27 Å, Crystal Structure of PCNA encoding the hypomorphic mutation S228I
1VYM 2.3 Å, Native human pcna

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