9BAW: Human importin beta-Ran-GTP heterodimer

Cryo-EM structure of human importin beta-Ran-GTP heterodimer. Determined by electron microscopy at 3.3 Å resolution. Released 8 Oct 2025.

Method: Electron microscopy
Resolution: 3.3 Å
Organism: Homo sapiens
Chains: 2
Atoms: 8,223
Mol. weight: 117.41 kDa
Ligands: MG, GTP
Released: 8 Oct 2025

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

Secondary structure: helices and β-sheets

9BAW contains 59 α-helices and 9 β-strands across 2 chains. 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: 53 helices, 0 β-strands

Element	Residues	Length
α-helix	3-9	7
α-helix	15-31	17
α-helix	33-44	12
α-helix	51-65	15
α-helix	70-81	12
α-helix	85-98	14
α-helix	109-123	15
α-helix	129-138	10
α-helix	144-160	17
α-helix	170-181	12
α-helix	188-201	14
α-helix	206-210	5
α-helix	212-225	14
α-helix	231-247	17
α-helix	249-251	3
α-helix	256-260	5
α-helix	261-268	8
α-helix	273-302	30
α-helix	314-317	4
α-helix	319-329	11
α-helix	344-359	16
α-helix	360-362	3
α-helix	364-374	11
α-helix	380-392	13
α-helix	399-417	19
α-helix	422-438	17
α-helix	440-443	4
α-helix	449-459	11
α-helix	464-483	20
α-helix	498-501	4
α-helix	503-514	12
α-helix	521-523	3
α-helix	524-537	14
α-helix	541-543	3
α-helix	544-562	19
α-helix	571-592	22
α-helix	597-617	21
α-helix	627-639	13
α-helix	641-645	5
α-helix	647-660	14
α-helix	664-681	18
α-helix	682-685	4
α-helix	686-698	13
α-helix	709-724	16
α-helix	725-730	6
α-helix	732-744	13
α-helix	753-776	24
α-helix	785-789	5
α-helix	793-806	14
α-helix	812-829	18
α-helix	831-838	8
α-helix	841-852	12
α-helix	856-875	20

Chain B: 6 helices, 9 β-strands

Element	Residues	Length	Sheet
β-strand	11-16	6	1
α-helix	23-31	9
β-strand	45-54	10	1
β-strand	57-66	10	1
α-helix	76-80	5
β-strand	85-91	7	1
α-helix	95-99	5
α-helix	101-109	9
β-strand	117-122	6	1
α-helix	138-141	4
β-strand	145-148	4	1
β-strand	150	1	2
β-strand	155	1	2
α-helix	159-169	11
β-strand	176	1	1

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Importin subunit beta-1	A	protein	876	Homo sapiens	Q14974 (AlphaFold model)
GTP-binding nuclear protein Ran	B	protein	170	Homo sapiens	P62826 (AlphaFold model)

Sequence of entity 1 (A), FASTA

>9BAW_1 Importin subunit beta-1 (chains A)
MELITILEKTVSPDRLELEAAQKFLERAAVENLPTFLVELSRVLANPGNSQVARVAAGLQ
IKNSLTSKDPDIKAQYQQRWLAIDANARREVKNYVLHTLGTETYRPSSASQCVAGIACAE
IPVNQWPELIPQLVANVTNPNSTEHMKESTLEAIGYICQDIDPEQLQDKSNEILTAIIQG
MRKEEPSNNVKLAATNALLNSLEFTKANFDKESERHFIMQVVCEATQCPDTRVRVAALQN
LVKIMSLYYQYMETYMGPALFAITIEAMKSDIDEVALQGIEFWSNVCDEEMDLAIEASEA
AEQGRPPEHTSKFYAKGALQYLVPILTQTLTKQDENDDDDDWNPCKAAGVCLMLLATCCE
DDIVPHVLPFIKEHIKNPDWRYRDAAVMAFGCILEGPEPSQLKPLVIQAMPTLIELMKDP
SVVVRDTAAWTVGRICELLPEAAINDVYLAPLLQCLIEGLSAEPRVASNVCWAFSSLAEA
AYEAADVADDQEEPATYCLSSSFELIVQKLLETTDRPDGHQNNLRSSAYESLMEIVKNSA
KDCYPAVQKTTLVIMERLQQVLQMESHIQSTSDRIQFNDLQSLLCATLQNVLRKVQHQDA
LQISDVVMASLLRMFQSTAGSGGVQEDALMAVSTLVEVLGGEFLKYMEAFKPFLGIGLKN
YAEYQVCLAAVGLVGDLCRALQSNIIPFCDEVMQLLLENLGNENVHRSVKPQILSVFGDI
ALAIGGEFKKYLEVVLNTLQQASQAQVDKSDYDMVDYLNELRESCLEAYTGIVQGLKGDQ
ENVHPDVMLVQPRVEFILSFIDHIAGDEDHTDGVVACAAGLIGDLCTAFGKDVLKLVEAR
PMIHELLTEGRRSKTNKAKTLARWATKELRKLKNQA

Sequence of entity 2 (B), FASTA

>9BAW_2 GTP-binding nuclear protein Ran (chains B)
VQFKLVLVGDGGTGKTTFVKRHLTGEFEKKYVATLGVEVHPLVFHTNRGPIKFNVWDTAG
QEKFGGLRDGYYIQAQCAIIMFDVTSRVTYKNVPNWHRDLVRVCENIPIVLCGNKVDIKD
RKVKAKSIVFHRKKNLQYYDISAKSNYNFEKPFLWLARKLIGDPNLEFAA

Ligands and cofactors

ID	Name	Formula	Copies
MG	Magnesium ion	Mg	1
GTP	Guanosine-5'-triphosphate	C10 H16 N5 O14 P3	1

Primary citation

Cryo-EM structure of human importin beta-Ran-GTP heterodimer. Ko, Y., Cingolani, G. To be published.

Other PDB entries of the same protein (UniProt Q14974 (AlphaFold model), which also has an AlphaFold model), best resolution first:

1IBR 2.3 Å, Complex of ran with importin beta
1QGR 2.3 Å, Structure of importin beta bound to the ibb domain of importin alpha (II crystal form,…
2P8Q 2.35 Å, Crystal Structure of human Importin beta bound to the Snurportin1 IBB-domain
1QGK 2.5 Å, Structure of importin beta bound to the ibb domain of importin alpha
3W5K 2.6 Å, Crystal structure of Snail1 and importin beta complex
9N85 2.6 Å, Cryo-EM structure of human importin beta:Ran-GTP:RanBP1 trimeric complex
1F59 2.8 Å, Importin-beta-fxfg nucleoporin complex
1O6O 2.8 Å, Importin Beta aa1-442 bound to five FxFG repeats from yeast Nsp1p. Second crystal form
1O6P 2.8 Å, Importin Beta bound to a GLFG Nucleoporin peptide
2QNA 2.84 Å, Crystal structure of human Importin-beta (127-876) in complex with the IBB-domain of…
1M5N 2.9 Å, Crystal structure of HEAT repeats (1-11) of importin b bound to the non-classical…
3LWW 3.15 Å, Structure of an open and closed conformation of Human Importin Beta bound to the…

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