22AK: GDP human alpha1A/beta3 microtubule

GDP human alpha1A/beta3 microtubule. Determined by electron microscopy at 2.41 Å resolution. Released 1 Apr 2026.

Method: Electron microscopy
Resolution: 2.41 Å
Organism: Homo sapiens
Chains: 2
Atoms: 6,811
Mol. weight: 101.68 kDa
Ligands: GTP, MG, GDP
Released: 1 Apr 2026

Explore 22AK in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

22AK contains 52 α-helices and 34 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: 25 helices, 16 β-strands

Element	Residues	Length	Sheet
β-strand	2-9	8	5
α-helix	10-28	19
β-strand	35	1	6
β-strand	53-55	3	7
β-strand	60	1	6
β-strand	61-63	3	7
β-strand	65-69	5	5
α-helix	73-79	7
α-helix	89-91	3
β-strand	92-94	3	5
α-helix	103-104	2
α-helix	105-109	5
α-helix	115-128	14
β-strand	131-140	10	5
α-helix	144	1
α-helix	145-149	5
α-helix	150-160	11
β-strand	165-172	8	5
α-helix	173-174	2
α-helix	183-194	12
β-strand	200-205	6	5
α-helix	206-215	10
α-helix	224-238	15
α-helix	240-242	3
β-strand	248	1	5
α-helix	252-259	8
β-strand	269-273	5	5
α-helix	281-283	3
α-helix	288-295	8
α-helix	298-300	3
α-helix	307-309	3
β-strand	312-320	9	5
α-helix	325-338	14
β-strand	343	1	5
β-strand	351-356	6	5
α-helix	359-363	5
α-helix	368-370	3
β-strand	374-381	8	5
α-helix	384-400	17
α-helix	405-409	5
α-helix	416-434	19

Chain B: 27 helices, 18 β-strands

Element	Residues	Length	Sheet
β-strand	2-9	8	1
α-helix	10-28	19
β-strand	30	1	2
β-strand	35	1	3
β-strand	36	1	2
α-helix	41-45	5
α-helix	47-49	3
β-strand	51-54	4	3
α-helix	55-57	3
β-strand	58-61	4	3
β-strand	63-67	5	1
α-helix	71-78	8
α-helix	87-89	3
β-strand	90-92	3	1
α-helix	101-102	2
α-helix	103-107	5
α-helix	113-126	14
β-strand	129-138	10	1
α-helix	143-147	5
α-helix	148-158	11
β-strand	163-170	8	1
α-helix	171-172	2
α-helix	181-192	12
β-strand	198-203	6	1
α-helix	204-209	6
α-helix	210-214	5
α-helix	225-236	12
α-helix	238-240	3
β-strand	246	1	4
α-helix	250-257	8
β-strand	265-266	2	1
β-strand	267-271	5	4
α-helix	279-281	3
α-helix	286-293	8
α-helix	296-298	3
α-helix	305-307	3
β-strand	310-318	9	4
α-helix	323-336	14
α-helix	338-340	3
β-strand	341	1	4
β-strand	349-354	6	4
β-strand	364-371	8	4
α-helix	374-390	17
α-helix	395-400	6
α-helix	406-426	21

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Tubulin beta-3 chain	B	protein	450	Homo sapiens	Q13509 (AlphaFold model)
Tubulin alpha-1A chain	A	protein	451	Homo sapiens	Q71U36 (AlphaFold model)

Sequence of entity 1 (B), FASTA

>22AK_1 Tubulin beta-3 chain (chains B)
MREIVHIQAGQCGNQIGAKFWEVISDEHGIDPSGNYVGDSDLQLERISVYYNEASSHKYV
PRAILVDLEPGTMDSVRSGAFGHLFRPDNFIFGQSGAGNNWAKGHYTEGAELVDSVLDVV
RKECENCDCLQGFQLTHSLGGGTGSGMGTLLISKVREEYPDRIMNTFSVVPSPKVSDTVV
EPYNATLSIHQLVENTDETYCIDNEALYDICFRTLKLATPTYGDLNHLVSATMSGVTTSL
RFPGQLNADLRKLAVNMVPFPRLHFFMPGFAPLTARGSQQYRALTVPELTQQMFDAKNMM
AACDPRHGRYLTVATVFRGRMSMKEVDEQMLAIQSKNSSYFVEWIPNNVKVAVCDIPPRG
LKMSSTFIGNSTAIQELFKRISEQFTAMFRRKAFLHWYTGEGMDEMEFTEAESNMNDLVS
EYQQYQDATAEEEGEMYEDDEEESEAQGPK

Sequence of entity 2 (A), FASTA

>22AK_2 Tubulin alpha-1A chain (chains A)
MRECISIHVGQAGVQIGNACWELYCLEHGIQPDGQMPSDKTIGGGDDSFNTFFSETGAGK
HVPRAVFVDLEPTVIDEVRTGTYRQLFHPEQLITGKEDAANNYARGHYTIGKEIIDLVLD
RIRKLADQCTGLQGFLVFHSFGGGTGSGFTSLLMERLSVDYGKKSKLEFSIYPAPQVSTA
VVEPYNSILTTHTTLEHSDCAFMVDNEAIYDICRRNLDIERPTYTNLNRLIGQIVSSITA
SLRFDGALNVDLTEFQTNLVPYPRIHFPLATYAPVISAEKAYHEQLSVAEITNACFEPAN
QMVKCDPRHGKYMACCLLYRGDVVPKDVNAAIATIKTKRTIQFVDWCPTGFKVGINYQPP
TVVPGGDLAKVQRAVCMLSNTTAIAEAWARLDHKFDLMYAKRAFVHWYVGEGMEEGEFSE
AREDMAALEKDYEEVGVDSVEGEGEEEGEEY

Ligands and cofactors

ID	Name	Formula	Copies
GTP	Guanosine-5'-triphosphate	C10 H16 N5 O14 P3	1
MG	Magnesium ion	Mg	2
GDP	Guanosine-5'-diphosphate	C10 H15 N5 O11 P2	1

Primary citation

An evolution-conserved allosteric network in human tubulin governs paclitaxel efficacy. Luo, J., Khoo, C.J., Chen, W. et al. Nat Chem Biol (2026). DOI 10.1038/s41589-026-02204-2 · PubMed

Other PDB entries of the same protein (UniProt Q13509 (AlphaFold model), which also has an AlphaFold model), best resolution first:

6S8L 1.8 Å, Structure, Thermodynamics, and Kinetics of Plinabulin Binding to two Tubulin Isotypes
7PJF 1.86 Å, Inhibiting parasite proliferation using a rationally designed anti-tubulin agent
9WD9 2.26 Å, GMPCPP-stabilized human alpha1A/beta3 S239C microtubule
9WD7 2.34 Å, GMPCPP-stabilizsd human alpha1A/beta3 microtubule
9WDA 2.35 Å, Paclitaxel/GMPCPP-stabilized human alpha1A/beta3 microtubule
9WDB 2.39 Å, Paclitaxel/GMPCPP-stabilized human alpha1A/beta3 S239C microtubule
22AJ 2.48 Å, GDP human alpha1A/beta3 S239C microtubule
8VT7 2.66 Å, Structure of the gamma tubulin ring complex nucleated microtubule protofilament.
7Z6S 2.9 Å, MATCAP bound to a human 14 protofilament microtubule
6WSL 3.1 Å, Cryo-EM structure of VASH1-SVBP bound to microtubules
7LXB 3.26 Å, HeLa-tubulin in complex with cryptophycin 52
7M18 3.38 Å, HeLa-tubulin in complex with cryptophycin 1

Browse structure collections

About this viewer

MolViewer shows 22AK directly in your browser with nothing to install. Switch between cartoon, ball-and-stick, spacefill and surface views, color by chain, secondary structure or B-factor, measure distances, angles and dihedrals, and share or embed the view.