10FI: Apo CCAN purified from budding yeast

apo CCAN purified from budding yeast. Determined by electron microscopy at 3.3 Å resolution. Released 8 Jul 2026.

Method: Electron microscopy
Resolution: 3.3 Å
Organism: Saccharomyces cerevisiae
Chains: 11
Atoms: 18,830
Mol. weight: 429.69 kDa
Released: 8 Jul 2026

Explore 10FI in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

10FI contains 101 α-helices and 62 β-strands across 11 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 H: 5 helices, 0 β-strands

Element	Residues	Length
α-helix	5-37	33
α-helix	47-49	3
α-helix	51-72	22
α-helix	83-92	10
α-helix	99-134	36

Chain I: 24 helices, 2 β-strands

Element	Residues	Length	Sheet
α-helix	334-339	6
α-helix	340-347	8
α-helix	355-368	14
α-helix	375-387	13
α-helix	390-400	11
α-helix	403-408	6
α-helix	410-420	11
α-helix	432-449	18
α-helix	457-473	17
α-helix	479-493	15
α-helix	507-523	17
α-helix	539-546	8
α-helix	551-565	15
α-helix	576-589	14
α-helix	590-594	5
β-strand	603	1	1
β-strand	606	1	1
α-helix	608-618	11
α-helix	627-629	3
α-helix	632-635	4
α-helix	640-653	14
α-helix	667-676	10
α-helix	678-684	7
α-helix	693-706	14
α-helix	712-721	10
α-helix	726-728	3

Chain K: 4 helices, 0 β-strands

Element	Residues	Length
α-helix	8-40	33
α-helix	51-53	3
α-helix	54-57	4
α-helix	75-126	52

Chain L: 9 helices, 16 β-strands

Element	Residues	Length	Sheet
β-strand	3-10	8	2
α-helix	20-27	8
β-strand	32-36	5	2
β-strand	39	1	3
β-strand	52	1	3
β-strand	54-59	6	2
β-strand	72-77	6	2
β-strand	85-89	5	2
α-helix	95-107	13
β-strand	112-113	2	2
α-helix	118-127	10
β-strand	130-132	3	4
β-strand	138-140	3	4
β-strand	145-149	5	2
α-helix	154-156	3
β-strand	160-165	6	2
α-helix	167-177	11
α-helix	183	1
α-helix	184-188	5
α-helix	189-196	8
β-strand	198	1	5
β-strand	205-209	5	2
β-strand	214-216	3	2
β-strand	220-223	4	2
α-helix	230-239	10

Chain N: 16 helices, 15 β-strands

Element	Residues	Length	Sheet
α-helix	17-24	8
α-helix	29-42	14
α-helix	53-63	11
α-helix	68-77	10
α-helix	86-99	14
α-helix	101-103	3
β-strand	106-113	8	6
β-strand	117-118	2	6
α-helix	125-137	13
β-strand	141-148	8	6
β-strand	154-163	10	6
β-strand	195-196	2	6
β-strand	200-205	6	6
β-strand	210-214	5	6
α-helix	219-233	15
β-strand	238-242	5	6
β-strand	248	1	6
α-helix	251-258	8
α-helix	262-264	3
α-helix	271-275	5
α-helix	290-293	4
β-strand	295-298	4	7
α-helix	299-301	3
α-helix	319-333	15
β-strand	384-393	10	2
β-strand	396-405	10	2
α-helix	409-418	10
β-strand	422	1	5
α-helix	429-432	4
β-strand	441-443	3	2
β-strand	447	1	2

Chain O: 6 helices, 15 β-strands

Element	Residues	Length	Sheet
α-helix	155-171	17
β-strand	175-180	6	8
β-strand	188	1	9
β-strand	195	1	9
β-strand	201-206	6	8
β-strand	209	1	10
β-strand	216	1	10
β-strand	220-226	7	8
β-strand	233-238	6	8
α-helix	246-252	7
α-helix	253-256	4
β-strand	258	1	8
α-helix	261-290	30
β-strand	297-298	2	11
β-strand	305-309	5	11
β-strand	314-319	6	11
β-strand	323	1	12
β-strand	324-330	7	11
α-helix	340-347	8
β-strand	351	1	12
α-helix	353-362	10

Chain P: 9 helices, 12 β-strands

Element	Residues	Length	Sheet
α-helix	98-109	12
β-strand	125-128	4	7
α-helix	134-139	6
α-helix	150-155	6
α-helix	156-160	5
β-strand	165-175	11	13
β-strand	180-189	10	13
β-strand	197-205	9	13
β-strand	212-220	9	13
α-helix	225-232	8
α-helix	237-265	29
β-strand	270-272	3	14
β-strand	279-284	6	14
β-strand	294-299	6	14
β-strand	301-303	3	15
β-strand	318-321	4	15
β-strand	323-326	4	14
β-strand	331	1	14
α-helix	332-333	2
α-helix	334-348	15
α-helix	351-362	12

Chain Q: 8 helices, 1 β-strand

Element	Residues	Length	Sheet
α-helix	162-183	22
α-helix	196-218	23
α-helix	235-291	57
α-helix	322-332	11
β-strand	334-336	3	15
α-helix	338-342	5
α-helix	350-356	7
α-helix	359-381	23
α-helix	383-390	8

3 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
Inner kinetochore subunit MCM16	H	protein	181	Saccharomyces cerevisiae	Q12262 (AlphaFold model)
Inner kinetochore subunit CTF3	I	protein	733	Saccharomyces cerevisiae	Q12748 (AlphaFold model)
Inner kinetochore subunit MCM22	K	protein	239	Saccharomyces cerevisiae	P47167 (AlphaFold model)
Inner kinetochore subunit IML3	L	protein	245	Saccharomyces cerevisiae	P38265 (AlphaFold model)
Inner kinetochore subunit CHL4	N	protein	458	Saccharomyces cerevisiae	P38907
Inner kinetochore subunit MCM21	O	protein	368	Saccharomyces cerevisiae	Q06675
Inner kinetochore subunit CTF19	P	protein	369	Saccharomyces cerevisiae	Q02732
Inner kinetochore subunit OKP1	Q	protein	406	Saccharomyces cerevisiae	P53298
K7_Ame1p	U	protein	324	Saccharomyces cerevisiae	G2W9L4
Inner kinetochore subunit NKP1	Y	protein	238	Saccharomyces cerevisiae	Q12493
Inner kinetochore subunit NKP2	Z	protein	153	Saccharomyces cerevisiae	Q06162

Sequence of entity 1 (H), FASTA

>10FI_1 Inner kinetochore subunit MCM16 (chains H)
MTNSSEKQWERIQQLEKEHVEVYRELLITLDRLYLIRKHNHAVILSHTQQRLLEIRHQLQ
INLEKTALLIRLLEKPDNTNVLFTKLQNLLEESNSLDYELLQSLGAQSSLHKQLIESRAE
RDELMSKLIELSSKFPKPTIPPDDSDTAGKQVEVEKENETIQELMIALQIHSGYTNISYT
I

Sequence of entity 2 (I), FASTA

>10FI_2 Inner kinetochore subunit CTF3 (chains I)
MSLILDDIILSLTNANERTPPQALKTTLSLLYEKSKQYGLSSPQLQALVRLLCETSIIDT
VTKVYIVENCFLPDGYLTKELLLEIINHLGTPTVFSRYRIQTPPVLQSALCKWLVHVYFL
FPVHSEREHNISSSIWLHLWQFSFLQKWITPLVIWQATTPVDVKPWKLSIIKRCAMHPGY
RDAPGSATLILQRFQCLVGASSQITESIITINCNRKTLKSHRNLKLDAHFLSILKRILSR
AHPANFPADTVQNTIDMYLSEIHQLGADSIYPLRLQSLPEYVPSDSTVSLWDVTSLEQLA
QNWPQLHIPNDVDYMMKPSLNSNVLLPRKVMSRDSLKHLYSSIILIKNSRDESSSPYEWC
IWQLKRCFAHQIETPQEVIPIIISVSSMDNKLSSRIIQTFCNLKYLKLDELTLKKVCGGI
LPLWKPELISGTREFFVKFMASIFMWSTRDGHDNNCTFSETCFYVLQMITNWVLDDKLIA
LGLTLLHDMQSLLTLDKIFNNATSNRFSTMAFISSLDILTQLSKQTKSDYAIQYLIVGPD
IMNKVFSSDDPLLLSAACRYLVATKNKLMQYPSTNKFVRMQNQYIMDLTNYLYRNKVLSS
KSLFGVSPDFFKQILENLYIPTADFKNAKFFTITGIPALSYICIIILRRLETAENTKIKF
TSGIINEETFNNFFRVHHDEIGQHGWIKGVNNIHDLRVKILMHLSNTANPYRDIAAFLFT
YLKSLSKYSVQNS

Sequence of entity 3 (K), FASTA

>10FI_3 Inner kinetochore subunit MCM22 (chains K)
MDVEKDVLDVYIKNLENQIGNKRYFLKQAQGAIDEITKRSLDTEGKPVNSEVFTELLRKP
MFFSERADPIGFSLTSNFLSLRAQSSSEWLSLMNDQSVDQKAMLLLQNNINSDLKELLRK
LQHQMTIMDSKKQDHAHIRTRKARNKELWDSLADFLKGYLVPNLDDNDESIDSLTNEVML
LMKRLIEHDLNLTLNDFSSKTIPIYRLLLRANIITVIEGSTNPGTKYIKLIDFNETSLT

Sequence of entity 4 (L), FASTA

>10FI_4 Inner kinetochore subunit IML3 (chains L)
MPYTWKFLGISKQLSLENGIAKLNQLLNLEVDLDIQTIRVPSDPDGGTAADEYIRYEMRL
DISNLDEGTYSKFIFLGNSKMEVPMFLCYCGTDNRNEVVLQWLKAEYGVIMWPIKFEQKT
MIKLADASIVHVTKENIEQITWFSSKLYFEPETQDKNLRQFSIEIPRESCEGLALGYGNT
MHPYNDAIVPYIYNETGMAVERLPLTSVILAGHTKIMRESIVTSTRSLRNRVLAVVLQSI
QFTSE

Sequence of entity 5 (N), FASTA

>10FI_5 Inner kinetochore subunit CHL4 (chains N)
MSNELRLEDNYVPTSDTLVVFKQLMKLPVTVLYDLTLSWFAKFGGSFDGDIYLLTETLDL
LIEKGVRRNVIVNRILYVYWPDGLNVFQLAEIDCHLMISKPEKFKWLPSKALRGDGKPYV
VKLQPAKFIENLQTDLAKIYHCHVYMFKHPSLPVLITRIQLFDSNNLFLSTPNIGSINKE
SLYNKLDKFQGKPLISRRPYYVAFPLNSPIIFHSVDKDIYARLVLQSISRTISERETIIF
KPVQKIPVKSIHNIMTLLGPSRFAESMGPWECYASANFERSPLHDYKKHQGLTGKKVMVR
EFDDSFLNDDENFYGKEEPEIRRLRLEKNMIKFKGSANGVMDQKYNDLKEFNEHVHNIRN
GKKNEDSGEPVYISRYSSLVPIEKVGFTLKNEINSRIITIKLKFNGNDIFGGLHELCDKN
LINIDKVPGWLAGENGSFSGTIMNGDFQREQVAKGGLL

Sequence of entity 6 (O), FASTA

>10FI_6 Inner kinetochore subunit MCM21 (chains O)
MSRIDDLQQDIESLLSEINSLEESREKLKAKIKDKRKNEESANPIVQEFEDLFDQFPQLN
NFLFNEHPELEETDDKDISRAQADIPATPIPYEPKKRAKLENEEILPEQEWVLKTQPMVQ
HQMFDPGVADLLDTDILTSPSKRKRKLKIDDISTSDRSELEDYIVLENVYRMFGITFFPL
VDPIDLKIKDASGEIFVDREMLGIRLEVFSERTSQFEKPHYVLLKKRIKSNSWFLFKHTI
PSFIDVQGIFDDTNGGLVISHDDAYLFAKRVFLQLVEVQKRRQIFKDLEAKKIIHDLDLD
LESSMVSFFVKDIKVELFVKQNEIVSCSILDDIHDFSQNNKSKWEIALLGSLDDLELKLN
HSFATIFK

Sequence of entity 7 (P), FASTA

>10FI_7 Inner kinetochore subunit CTF19 (chains P)
MDFTSDTTNSHDTSNSHLSLEDAVGTHHAGEADVNIDGDEKQQLSLLDDDQVRALKLQEE
KDALLTRRNTLLQEIQTYQNILMKENNSKTKNGDILQNDITQDFLNLISISSSNPNSAIS
DRKRVERINGLTNLQKELVTKYDTLPLLNMNLRLSYLRDHTYPHLQVSVQSRDRVHNDGI
EVLVVNYKFCRNTMNPFEIQFKMFYKFEDSTLLKWEILRISTNVRLKAKQLLATRNFQKC
LLSLYEFDKIKSKKTGIFQNLINLLKRKTRCYLMNNSDSLIVERVIREGRLTTIKLQINF
IITMPGERGKPRNCFLPMSKISIALWKGGERFNQIDLDEICYGLIKEYGVKTGLKEICNV
CLFPDMYAR

Sequence of entity 8 (Q), FASTA

>10FI_8 Inner kinetochore subunit OKP1 (chains Q)
MAADRDNFLQNIENDSINNGQAMDLSPNRSSSESDSSILMNVNDIKTLRLDVAPEAKSTQ
SKKSLFYENSDDAEEGEIEERTNKEEGQYHHKGSKQLRFEVGKESTGKLQSHLSDGSATS
GEGNVRPWEFRKVIQAEYRERLPRNYELKHWKKPSKIMIGSILRLLETNTVSALDSVFEK
YEKEMNQMTHGDNNEVKRIYSKKERLLEIILTKIKKKLRQAKFPSRISERDLDIEYIYSK
RQFIQNRYSQELQNNERLEAILSREQNLLEETRKLCMNLKTNNKKRLTEKLIQKDLHPVL
NKAMEYTYGLESTNGFMHPDGPVTFRNDSHELNLMLNDPIKSTADVRLDKEEVLSLLPSL
KEYTKKSKELKETMGQMISDSHEEEIKEVFVPHHESHQDKTEEDIH

Sequence of entity 9 (U), FASTA

>10FI_9 K7_Ame1p (chains U)
MDRDTKLAFRLRGSHSRRTDDIDDDVIVFKTPNAVYREENSPIQSPVQPILSSPKLANSF
EFPITTNNVNAQDRHEHGYQPLDAEDYPMIDSENKSPISESPQNVRNDEDLTTRYNFDDI
PIRQLSSSITSVTTIDVLSSLFINLFENDLIPQALKDFNKSDDDQFRKLLYKLDLRLFQT
ISDQMTRDLKDILDINVSNNELCYQLKQVLARKEDLNQQIISVRNEIQELKAGKDWHDLQ
NEQAKLNDKVKLNKRLNDLTSTLLGKYEEDRKIMSQDSEDDSIRDDSNILDIAHFVDLMD
PYNGLLKKINKINENLSNELQPSL

Sequence of entity 10 (Y), FASTA

>10FI_10 Inner kinetochore subunit NKP1 (chains Y)
MTDTYNSISNFIENELTALLSSDDYLMDDLAGELPNEVCRLLKAQVIEKRKDAMSRGKQD
LLSKEIYDNESELRASQSQQIMELVGDIPKYSLGSELRNRVEGEPQSTSIERLIEDVLKL
PQMEVADEEEVEVENDLKVLSEYSNLRKDLILKCQALQIGESKLSDILSQTNSINSLTTS
IKEASEDDDISEYFATYNGKLVVALEEMKLLLEEAVKTFGNSPEKREKIKKILSELKK

Sequence of entity 11 (Z), FASTA

>10FI_11 Inner kinetochore subunit NKP2 (chains Z)
MNSEQLLHNYVSDSLLTTLISFQEFKQQLQSYTSDEQQLQHWYELLQARDARVTSELEAR
IKQFFITLRSRLLRFLESEQLSHSLSLETLIDALYKINDLLQQRLQILDDAIQEKTSELA
EFENMVRSPSAGDNAIPGLLQIIQSYINLLEEN

Primary citation

Native yeast kinetochore structures identify an essential inner kinetochore interaction. Mengqiu, J., Sue, B. To be published.

Other PDB entries of the same protein (UniProt Q12262 (AlphaFold model), which also has an AlphaFold model), best resolution first:

6YPC 2.9 Å, Crystal structure of the kinetochore subunits H/I/K/T/W penta-complex from S. cerevisiae…
6WUC 3.23 Å, The yeast Ctf3 complex with Cnn1-Wip1
8OVW 3.4 Å, Cryo-EM structure of CBF1-CCAN bound topologically to centromeric DNA
8OW0 3.4 Å, Cryo-EM structure of CBF1-CCAN bound topologically to a centromeric CENP-A nucleosome
6QLE 3.55 Å, Structure of inner kinetochore CCAN complex
7L7Q 3.7 Å, Ctf3c with Ulp2-KIM
8OW1 3.7 Å, Cryo-EM structure of the yeast Inner kinetochore bound to a CENP-A nucleosome.
10DQ 3.9 Å, Cbf1-CCAN-CEN complex
6QLD 4.15 Å, Structure of inner kinetochore CCAN-Cenp-A complex
6OUA 4.18 Å, Cryo-EM structure of the yeast Ctf3 complex
10JC 6.5 Å, CCAN dimer purified from budding yeast

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