9N9G: Human Hec1-Nuf2 dimer

Cryo-EM structure of the human Hec1-Nuf2 dimer bound to the paclitaxel-stabilized microtubule. Determined by electron microscopy at 3.0 Å resolution. Released 4 Feb 2026.

Method: Electron microscopy
Resolution: 3.0 Å
Organisms: Homo sapiens, Sus scrofa
Chains: 9
Atoms: 20,986
Mol. weight: 535.95 kDa
Ligands: GTP, MG, GDP, TA1
Released: 4 Feb 2026

Explore 9N9G in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9N9G contains 139 α-helices and 65 β-strands across 9 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 1: 1 helix, 0 β-strands

Element	Residues	Length	Sheet
α-helix	15-18	4

Chain a: 24 helices, 14 β-strands

Element	Residues	Length	Sheet
β-strand	5-9	5	9
α-helix	10-28	19
α-helix	48-51	4
β-strand	53-55	3	10
β-strand	61-63	3	10
β-strand	65-69	5	9
α-helix	72-80	9
α-helix	89-91	3
β-strand	92-94	3	9
α-helix	103-104	2
α-helix	105-110	6
α-helix	111-128	18
β-strand	135-140	6	9
α-helix	144-160	17
β-strand	166-172	7	9
α-helix	183-196	14
β-strand	200-205	6	9
α-helix	206-215	10
α-helix	224-243	20
β-strand	248	1	11
α-helix	252-259	8
β-strand	269-273	5	11
α-helix	278-283	6
α-helix	288-294	7
α-helix	298-300	3
α-helix	307-309	3
β-strand	312-321	10	11
α-helix	325-337	13
β-strand	343	1	11
β-strand	351-356	6	11
α-helix	358-360	3
α-helix	362-363	2
α-helix	369-370	2
β-strand	373-381	9	11
α-helix	383-400	18
α-helix	405-411	7
α-helix	415-437	23
α-helix	440-450	11

Chain A: 25 helices, 14 β-strands

Element	Residues	Length	Sheet
β-strand	5-9	5	1
α-helix	10-28	19
α-helix	48-51	4
β-strand	53-55	3	2
β-strand	61-63	3	2
β-strand	65-69	5	1
α-helix	73-80	8
β-strand	92-94	3	1
α-helix	103-104	2
α-helix	105-109	5
α-helix	111-126	16
β-strand	134-140	7	1
α-helix	144	1
α-helix	145-149	5
α-helix	150-161	12
β-strand	165-172	8	1
α-helix	183-196	14
β-strand	200-205	6	1
α-helix	206-217	12
α-helix	224-243	20
β-strand	248	1	3
α-helix	252-259	8
β-strand	269-273	5	3
α-helix	278-283	6
α-helix	288-294	7
α-helix	298-300	3
α-helix	307-309	3
β-strand	312-321	10	3
α-helix	325-337	13
β-strand	343	1	3
β-strand	352-356	5	3
α-helix	358-360	3
α-helix	362-363	2
α-helix	369-370	2
β-strand	373-381	9	3
α-helix	384-401	18
α-helix	405-410	6
α-helix	416-436	21
α-helix	439-449	11

Chain b: 24 helices, 17 β-strands

Element	Residues	Length	Sheet
β-strand	3-9	7	12
α-helix	10-28	19
β-strand	30	1	13
β-strand	36	1	13
α-helix	41-47	5
α-helix	49-51	3
β-strand	53-56	4	14
β-strand	60-63	4	14
β-strand	65-69	5	12
α-helix	72-80	9
α-helix	89-91	3
β-strand	92-94	3	12
α-helix	103-104	2
α-helix	105-110	6
α-helix	111-128	18
β-strand	132-140	9	12
α-helix	145-149	5
α-helix	150-160	11
β-strand	166-171	6	12
α-helix	183-197	15
β-strand	200-204	5	12
α-helix	206-215	10
α-helix	224-239	16
α-helix	240-242	3
β-strand	248	1	15
α-helix	252-259	8
β-strand	267-268	2	12
β-strand	269-273	5	15
α-helix	288-295	8
α-helix	307-309	3
β-strand	312-320	9	15
α-helix	325-338	14
α-helix	340-342	3
β-strand	343	1	15
β-strand	351-356	6	15
α-helix	359-360	2
β-strand	374-381	8	15
α-helix	382-384	3
α-helix	385-399	15
α-helix	405-411	7
α-helix	415-444	30

Chain B: 23 helices, 18 β-strands

Element	Residues	Length	Sheet
β-strand	3-8	6	4
α-helix	12-28	17
β-strand	30	1	5
β-strand	35	1	6
β-strand	36	1	5
α-helix	41-47	5
α-helix	49-51	3
β-strand	53-56	4	6
β-strand	60-63	4	6
β-strand	65-69	5	4
α-helix	73-80	8
α-helix	89-91	3
β-strand	92-94	3	4
α-helix	103-104	2
α-helix	105-110	6
α-helix	111-127	17
β-strand	132-140	9	4
α-helix	145-160	16
β-strand	165-171	7	4
α-helix	183-197	15
β-strand	200-204	5	4
α-helix	206-215	10
α-helix	224-243	20
β-strand	248	1	7
α-helix	252-259	8
β-strand	267-268	2	4
β-strand	269-273	5	7
α-helix	288-295	8
α-helix	298-300	3
α-helix	307-309	3
β-strand	312-320	9	7
α-helix	325-338	14
α-helix	340-342	3
β-strand	343	1	7
β-strand	351-356	6	7
α-helix	359-360	2
β-strand	374-381	8	7
α-helix	384-399	16
α-helix	405-411	7
α-helix	416-436	21
α-helix	441-454	14

Chain f: 9 helices, 0 β-strands

Element	Residues	Length
α-helix	11-21	11
α-helix	25-30	6
α-helix	33-35	3
α-helix	42-57	16
α-helix	61-65	5
α-helix	76-79	4
α-helix	83-98	16
α-helix	107-110	4
α-helix	114-177	64

Chain F: 9 helices, 0 β-strands

Element	Residues	Length
α-helix	11-20	10
α-helix	25-28	4
α-helix	42-57	16
α-helix	61-63	3
α-helix	66-68	3
α-helix	76-79	4
α-helix	83-95	13
α-helix	106-110	5
α-helix	114-176	63

Chain n: 10 helices, 0 β-strands

Element	Residues	Length
α-helix	79-82	4
α-helix	89-106	18
α-helix	114-117	4
α-helix	122-134	13
α-helix	147-157	11
α-helix	166-170	5
α-helix	178-200	23
α-helix	222-238	17
α-helix	244-258	15
α-helix	262-288	27

1 more chain groups are not listed. Open the entry in the viewer and use the sequence panel to see them.

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Kinetochore protein NDC80 homolog	1, N, n	protein	645	Homo sapiens	O14777 (AlphaFold model)
Tubulin alpha-1B chain	A, a	protein	451	Sus scrofa	Q2XVP4 (AlphaFold model)
Tubulin beta chain	B, b	protein	445	Sus scrofa	P02554 (AlphaFold model)
Kinetochore protein Nuf2	F, f	protein	467	Homo sapiens	Q9BZD4 (AlphaFold model)

Sequence of entity 1 (1, N, n), FASTA

>9N9G_1 Kinetochore protein NDC80 homolog (chains 1, N, n)
AGTMKRSSVSSGGAGRLSMQELRSQDVNKQGLYTPQTKEKPTFGKLSINKPTSERKVSLF
GKRTSGHGSRNSQLGIFSSSEKIKDPRPLNDKAFIQQCIRQLCEFLTENGYAHNVSMKSL
QAPSVKDFLKIFTFLYGFLCPSYELPDTKFEEEVPRIFKDLGYPFALSKSSMYTVGAPHT
WPHIVAALVWLIDCIKIHTAMKESSPLFDDGQPWGEETEDGIMHNKLFLDYTIKCYESFM
SGADSFDEMNAELQSKLKDLFNVDAFKLESLEAKNRALNEQIARLEQEREKEPNRLESLR
KLKASLQGDVQKYQAYMSNLESHSAILDQKLNGLNEEIARVELECETIKQENTRLQNIID
NQKYSVADIERINHERNELQQTINKLTKDLEAEQQKLWNEELKYARGKEAIETQLAEYHK
LARKLKLIPKGAENSKGYDFEIKFNPEAGANCLVKYRAQVYVPLKELLNETEEEINKALN
KKMGLEDTLEQLNAMITESKRSVRTLKEEVQKLDDLYQQKIKEAEEEDEKCASELESLEK
HKHLLESTVNQGLSEAMNELDAVQREYQLVVQTTTEERRKVGNNLQRLLEMVATHVGSVE
KHLEEQIAKVDREYEECMSEDLSENIKEIRDKYEKKATLIKSSEE

Sequence of entity 2 (A, a), FASTA

>9N9G_2 Tubulin alpha-1B chain (chains A, a)
MRECISIHVGQAGVQIGNACWELYCLEHGIQPDGQMPSDKTIGGGDDSFNTFFSETGAGK
HVPRAVFVDLEPTVIDEVRTGTYRQLFHPEQLITGKEDAANNYARGHYTIGKEIIDLVLD
RIRKLADQCTGLQGFLVFHSFGGGTGSGFTSLLMERLSVDYGKKSKLEFSIYPAPQVSTA
VVEPYNSILTTHTTLEHSDCAFMVDNEAIYDICRRNLDIERPTYTNLNRLISQIVSSITA
SLRFDGALNVDLTEFQTNLVPYPRIHFPLATYAPVISAEKAYHEQLSVAEITNACFEPAN
QMVKCDPRHGKYMACCLLYRGDVVPKDVNAAIATIKTKRSIQFVDWCPTGFKVGINYQPP
TVVPGGDLAKVQRAVCMLSNTTAIAEAWARLDHKFDLMYAKRAFVHWYVGEGMEEGEFSE
AREDMAALEKDYEEVGVDSVEGEGEEEGEEY

Sequence of entity 3 (B, b), FASTA

>9N9G_3 Tubulin beta chain (chains B, b)
MREIVHIQAGQCGNQIGAKFWEVISDEHGIDPTGSYHGDSDLQLERINVYYNEAAGNKYV
PRAILVDLEPGTMDSVRSGPFGQIFRPDNFVFGQSGAGNNWAKGHYTEGAELVDSVLDVV
RKESESCDCLQGFQLTHSLGGGTGSGMGTLLISKIREEYPDRIMNTFSVVPSPKVSDTVV
EPYNATLSVHQLVENTDETYCIDNEALYDICFRTLKLTTPTYGDLNHLVSATMSGVTTCL
RFPGQLNADLRKLAVNMVPFPRLHFFMPGFAPLTSRGSQQYRALTVPELTQQMFDAKNMM
AACDPRHGRYLTVAAVFRGRMSMKEVDEQMLNVQNKNSSYFVEWIPNNVKTAVCDIPPRG
LKMSATFIGNSTAIQELFKRISEQFTAMFRRKAFLHWYTGEGMDEMEFTEAESNMNDLVS
EYQQYQDATADEQGEFEEEGEEDEA

Sequence of entity 4 (F, f), FASTA

>9N9G_4 Kinetochore protein Nuf2 (chains F, f)
AGTMETLSFPRYNVAEIVIHIRNKILTGADGKNLTKNDLYPNPKPEVLHMIYMRALQIVY
GIRLEHFYMMPVNSEVMYPHLMEGFLPFSNLVTHLDSFLPICRVNDFETADILCPKAKRT
SRFLSGIINFIHFREACRETYMEFLWQYKSSADKMQQLNAAHQEALMKLERLDSVPVEEQ
EEFKQLSDGIQELQQSLNQDFHQKTIVLQEGNSQKKSNISEKTKRLNELKLSVVSLKEIQ
ESLKTKIVDSPEKLKNYKEKMKDTVQKLKNARQEVVEKYEIYGDSVDCLPSCQLEVQLYQ
KKIQDLSDNREKLASILKESLNLEDQIESDESELKKLKTEENSFKRLMIVKKEKLATAQF
KINKKHEDVKQYKRTVIEDCNKVQEKRGAVYERVTTINQEIQKIKLGIQQLKDAAEREKL
KSQEIFLNLKTALEKYHDGIEKAAEDSYAKIDEKTAELKRKMFKMST

Ligands and cofactors

ID	Name	Formula	Copies
GTP	Guanosine-5'-triphosphate	C10 H16 N5 O14 P3	2
MG	Magnesium ion	Mg	4
GDP	Guanosine-5'-diphosphate	C10 H15 N5 O11 P2	2
TA1	Taxol	C47 H51 N O14	2

Primary citation

Cryo-EM structure of the human Hec1-Nuf2 dimer bound to the paclitaxel-stabilized microtubule. Funabiki, H., Niu, Y. Sci Adv (2026).

Other PDB entries of the same protein (UniProt O14777 (AlphaFold model), which also has an AlphaFold model), best resolution first:

2IGP 1.8 Å, Crystal Structure of Hec1 CH domain
8G0P 2.0 Å, Crystal structure of the human Ndc80:Nuf2 loop region
2VE7 2.88 Å, Crystal structure of a bonsai version of the human Ndc80 complex
3IZ0 8.6 Å, Human Ndc80 Bonsai Decorated Microtubule

Browse structure collections

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