9OX7: Tubulin beta-2B chain

In situ microtubule structure in the axon of a human neuron. Determined by electron microscopy at 2.69 Å resolution. Released 18 Mar 2026.

Method: Electron microscopy
Resolution: 2.69 Å
Organism: Homo sapiens
Chains: 8
Atoms: 26,980
Mol. weight: 404.72 kDa
Ligands: GTP, MG, GDP
Released: 18 Mar 2026

Explore 9OX7 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9OX7 contains 199 α-helices and 137 β-strands across 8 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: 24 helices, 17 β-strands

Element	Residues	Length	Sheet
β-strand	4-9	6	19
α-helix	10-27	18
β-strand	35	1	20
α-helix	46-51	6
β-strand	53-55	3	21
α-helix	56	1
β-strand	60	1	20
β-strand	61-63	3	21
β-strand	65-69	5	19
α-helix	73-80	8
α-helix	89-91	3
β-strand	92-94	3	19
α-helix	103-104	2
α-helix	105-109	5
α-helix	112-126	15
β-strand	134-140	7	19
α-helix	144-160	17
β-strand	165-172	8	19
α-helix	183-189	7
α-helix	191-196	6
β-strand	200-205	6	19
α-helix	206-215	10
α-helix	224-243	20
β-strand	248	1	19
α-helix	252-259	8
β-strand	269	1	19
β-strand	272-273	2	19
α-helix	281-283	3
α-helix	288-294	7
α-helix	298-300	3
α-helix	307-309	3
β-strand	312-321	10	19
α-helix	325-337	13
β-strand	343	1	19
β-strand	351-356	6	19
α-helix	359-361	3
α-helix	369-370	2
β-strand	373-381	9	19
α-helix	384-399	16
α-helix	405-409	5
α-helix	416-434	19

Chain B: 27 helices, 18 β-strands

Element	Residues	Length	Sheet
β-strand	3-9	7	1
α-helix	10-28	19
β-strand	30	1	2
β-strand	35	1	3
β-strand	36	1	2
α-helix	42-45	4
α-helix	47-49	3
β-strand	51-54	4	3
β-strand	58-61	4	3
β-strand	63-67	5	1
α-helix	71-77	7
α-helix	82-84	3
α-helix	87-89	3
β-strand	90-92	3	1
α-helix	101-102	2
α-helix	103-107	5
α-helix	108-126	19
β-strand	130-138	9	1
α-helix	143-147	5
α-helix	148-158	11
β-strand	163-170	8	1
α-helix	171	1
α-helix	181-195	15
β-strand	198-203	6	1
α-helix	204-209	6
α-helix	210-214	5
α-helix	222-236	15
β-strand	246	1	4
α-helix	250-257	8
β-strand	265-266	2	1
β-strand	267-271	5	4
α-helix	276-281	6
α-helix	286-294	9
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
α-helix	357-358	2
β-strand	364-371	8	4
α-helix	374-389	16
α-helix	395-400	6
α-helix	405-425	21

Chain C: 23 helices, 16 β-strands

Element	Residues	Length	Sheet
β-strand	4-9	6	22
α-helix	10-27	18
β-strand	35	1	23
α-helix	46-51	6
β-strand	53-55	3	24
β-strand	60	1	23
β-strand	61-63	3	24
β-strand	65-69	5	22
α-helix	73-80	8
β-strand	92-94	3	22
α-helix	103-104	2
α-helix	105-109	5
α-helix	112-126	15
β-strand	134-140	7	22
α-helix	144-160	17
β-strand	165-172	8	22
α-helix	183-189	7
α-helix	191-196	6
β-strand	200-205	6	22
α-helix	206-215	10
α-helix	224-243	20
β-strand	246-248	3	22
α-helix	252-259	8
β-strand	269-273	5	22
α-helix	281-283	3
α-helix	288-294	7
α-helix	298-300	3
α-helix	307-309	3
β-strand	312-321	10	22
α-helix	325-337	13
β-strand	343	1	22
β-strand	351-356	6	22
α-helix	359-360	2
α-helix	362-363	2
α-helix	369-370	2
β-strand	373-381	9	22
α-helix	384-400	17
α-helix	405-410	6
α-helix	416-434	19

Chain D: 27 helices, 18 β-strands

Element	Residues	Length	Sheet
β-strand	3-9	7	5
α-helix	10-27	18
β-strand	30	1	6
β-strand	35	1	7
β-strand	36	1	6
α-helix	41-45	5
α-helix	47-49	3
β-strand	51-54	4	7
β-strand	58-61	4	7
β-strand	63-67	5	5
α-helix	71-77	7
α-helix	82-84	3
α-helix	87-89	3
β-strand	90-92	3	5
α-helix	101-102	2
α-helix	103-107	5
α-helix	108-126	19
β-strand	130-138	9	5
α-helix	143-147	5
α-helix	148-158	11
β-strand	163-170	8	5
α-helix	171	1
α-helix	181-195	15
β-strand	198-203	6	5
α-helix	204-209	6
α-helix	210-214	5
α-helix	222-236	15
β-strand	246	1	8
α-helix	250-257	8
β-strand	265-266	2	5
β-strand	267-271	5	8
α-helix	276-281	6
α-helix	286-293	8
α-helix	296-298	3
α-helix	305-307	3
β-strand	310-318	9	8
α-helix	323-336	14
α-helix	338-340	3
β-strand	341	1	8
β-strand	349-354	6	8
α-helix	357-358	2
β-strand	364-371	8	8
α-helix	374-389	16
α-helix	395-400	6
α-helix	405-425	21

Chain E: 26 helices, 19 β-strands

Element	Residues	Length	Sheet
β-strand	3-9	7	9
α-helix	10-28	19
β-strand	30	1	10
β-strand	35	1	11
β-strand	36	1	10
α-helix	41-45	5
α-helix	47-49	3
β-strand	51-53	3	12
β-strand	58	1	11
β-strand	59-61	3	12
β-strand	63-67	5	9
α-helix	71-77	7
α-helix	82-84	3
α-helix	87-89	3
β-strand	90-92	3	9
α-helix	101-102	2
α-helix	103-107	5
α-helix	108-126	19
β-strand	130-138	9	9
α-helix	143-147	5
α-helix	148-158	11
β-strand	163-170	8	9
α-helix	171	1
α-helix	181-195	15
β-strand	198-203	6	9
α-helix	204-209	6
α-helix	210-214	5
α-helix	222-236	15
β-strand	246	1	13
α-helix	250-257	8
β-strand	265-266	2	9
β-strand	267-271	5	13
α-helix	276-281	6
α-helix	286-294	9
α-helix	296-298	3
α-helix	305-307	3
β-strand	310-318	9	13
α-helix	323-336	14
α-helix	338-340	3
β-strand	341	1	13
β-strand	349-354	6	13
β-strand	364-371	8	13
α-helix	374-389	16
α-helix	395-400	6
α-helix	405-425	21

Chain F: 26 helices, 19 β-strands

Element	Residues	Length	Sheet
β-strand	3-9	7	14
α-helix	10-28	19
β-strand	30	1	15
β-strand	35	1	16
β-strand	36	1	15
α-helix	42-45	4
α-helix	47-49	3
β-strand	51-53	3	17
β-strand	58	1	16
β-strand	59-61	3	17
β-strand	63-67	5	14
α-helix	71-77	7
α-helix	87-89	3
β-strand	90-92	3	14
α-helix	101-102	2
α-helix	103-107	5
α-helix	108-126	19
β-strand	130-138	9	14
α-helix	143-147	5
α-helix	148-158	11
β-strand	163-170	8	14
α-helix	171	1
α-helix	181-195	15
β-strand	198-203	6	14
α-helix	204-209	6
α-helix	210-214	5
α-helix	222-236	15
β-strand	246	1	18
α-helix	250-257	8
β-strand	265-266	2	14
β-strand	267-271	5	18
α-helix	276-281	6
α-helix	286-293	8
α-helix	296-298	3
α-helix	305-307	3
β-strand	310-318	9	18
α-helix	323-336	14
α-helix	338-340	3
β-strand	341	1	18
β-strand	349-354	6	18
α-helix	357-358	2
β-strand	364-371	8	18
α-helix	374-389	16
α-helix	395-400	6
α-helix	405-425	21

Chain G: 21 helices, 16 β-strands

Element	Residues	Length	Sheet
β-strand	4-9	6	25
α-helix	10-27	18
α-helix	46-51	6
β-strand	53-55	3	26
β-strand	61-63	3	26
β-strand	65-69	5	25
α-helix	73-80	8
α-helix	89-91	3
β-strand	92-94	3	25
α-helix	103-104	2
α-helix	105-109	5
α-helix	112-126	15
β-strand	134-140	7	25
α-helix	144-160	17
β-strand	165-172	8	25
α-helix	183-196	14
β-strand	200-205	6	25
α-helix	206-215	10
α-helix	224-243	20
β-strand	248	1	25
α-helix	252-259	8
β-strand	262	1	27
β-strand	265	1	27
β-strand	269-273	5	25
α-helix	278-281	4
α-helix	288-295	8
α-helix	298-300	3
β-strand	312-321	10	25
α-helix	325-337	13
β-strand	343	1	25
β-strand	351-356	6	25
α-helix	359-361	3
α-helix	369-370	2
β-strand	373-381	9	25
α-helix	384-401	18
α-helix	405-410	6
α-helix	415-435	21

Chain H: 25 helices, 14 β-strands

Element	Residues	Length	Sheet
β-strand	4-9	6	28
α-helix	10-27	18
α-helix	48-51	4
β-strand	53-55	3	29
β-strand	61-63	3	29
β-strand	65-69	5	28
α-helix	73-80	8
α-helix	89-91	3
β-strand	92-94	3	28
α-helix	103-104	2
α-helix	105-109	5
α-helix	111-113	3
α-helix	115-127	13
β-strand	134-140	7	28
α-helix	144-160	17
β-strand	165-172	8	28
α-helix	183-189	7
α-helix	191-192	2
α-helix	193-197	5
β-strand	200-205	6	28
α-helix	206-215	10
α-helix	224-243	20
β-strand	246-248	3	28
α-helix	252-259	8
β-strand	269-273	5	28
α-helix	281-283	3
α-helix	288-294	7
α-helix	298-300	3
α-helix	307-309	3
β-strand	312-321	10	28
α-helix	325-337	13
β-strand	343	1	28
β-strand	351-356	6	28
α-helix	359-360	2
α-helix	369-370	2
β-strand	373-381	9	28
α-helix	384-399	16
α-helix	405-410	6
α-helix	416-434	19

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Tubulin beta-2B chain	B, D, E, F	protein	445	Homo sapiens	Q9BVA1 (AlphaFold model)
Tubulin alpha-1A chain	A, C, G, H	protein	451	Homo sapiens	Q71U36 (AlphaFold model)

Sequence of entity 1 (B, D, E, F), FASTA

>9OX7_1 Tubulin beta-2B chain (chains B, D, E, F)
MREIVHIQAGQCGNQIGAKFWEVISDEHGIDPTGSYHGDSDLQLERINVYYNEATGNKYV
PRAILVDLEPGTMDSVRSGPFGQIFRPDNFVFGQSGAGNNWAKGHYTEGAELVDSVLDVV
RKESESCDCLQGFQLTHSLGGGTGSGMGTLLISKIREEYPDRIMNTFSVMPSPKVSDTVV
EPYNATLSVHQLVENTDETYCIDNEALYDICFRTLKLTTPTYGDLNHLVSATMSGVTTCL
RFPGQLNADLRKLAVNMVPFPRLHFFMPGFAPLTSRGSQQYRALTVPELTQQMFDSKNMM
AACDPRHGRYLTVAAIFRGRMSMKEVDEQMLNVQNKNSSYFVEWIPNNVKTAVCDIPPRG
LKMSATFIGNSTAIQELFKRISEQFTAMFRRKAFLHWYTGEGMDEMEFTEAESNMNDLVS
EYQQYQDATADEQGEFEEEEGEDEA

Sequence of entity 2 (A, C, G, H), FASTA

>9OX7_2 Tubulin alpha-1A chain (chains A, C, G, H)
MRECISIHVGQAGVQIGNACWELYCLEHGIQPDGQMPSDKTIGGGDDSFNTFFSETGAGK
HVPRAVFVDLEPTVIDEVRTGTYRQLFHPEQLITGKEDAANNYARGHYTIGKEIIDLVLD
RIRKLADQCTGLQGFLVFHSFGGGTGSGFTSLLMERLSVDYGKKSKLEFSIYPAPQVSTA
VVEPYNSILTTHTTLEHSDCAFMVDNEAIYDICRRNLDIERPTYTNLNRLIGQIVSSITA
SLRFDGALNVDLTEFQTNLVPYPRIHFPLATYAPVISAEKAYHEQLSVAEITNACFEPAN
QMVKCDPRHGKYMACCLLYRGDVVPKDVNAAIATIKTKRTIQFVDWCPTGFKVGINYQPP
TVVPGGDLAKVQRAVCMLSNTTAIAEAWARLDHKFDLMYAKRAFVHWYVGEGMEEGEFSE
AREDMAALEKDYEEVGVDSVEGEGEEEGEEY

Ligands and cofactors

ID	Name	Formula	Copies
GTP	Guanosine-5'-triphosphate	C10 H16 N5 O14 P3	4
MG	Magnesium ion	Mg	4
GDP	Guanosine-5'-diphosphate	C10 H15 N5 O11 P2	4

Primary citation

Microtubules in the axon are GDP bound but adopt a stable GTP-like expanded state. Zehr, E.A., Sun, S., Sarbanes, S.L. et al. Nat Struct Mol Biol (2026) 33:631-640. DOI 10.1038/s41594-026-01787-7 · PubMed

Other PDB entries of the same protein (UniProt Q9BVA1 (AlphaFold model), which also has an AlphaFold model), best resolution first:

7ZCW 3.6 Å, Cryo-EM structure of GMPCPP-microtubules in complex with VASH2-SVBP
6E7C 3.65 Å, 14-pf 3-start GMPCPP-human alpha1B/beta2B microtubules

Browse structure collections

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