9TMN: Proteasome subunit alpha type-6

Human sperm 20S proteasome complex isolated from native source. Determined by electron microscopy at 1.85 Å resolution. Released 9 Sept 2026.

Method: Electron microscopy
Resolution: 1.85 Å
Organism: Homo sapiens
Chains: 30
Atoms: 51,258
Mol. weight: 718.49 kDa
Ligands: MG
Released: 9 Sept 2026

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

Secondary structure: helices and β-sheets

9TMN contains 239 α-helices and 402 β-strands across 30 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.

Chains a and M: 5 helices, 13 β-strands

Element	Residues	Length	Sheet
β-strand	11-16	6	99
β-strand	21-26	6	99
β-strand	29-31	3	43
β-strand	34-37	4	43
β-strand	43-47	5	100
β-strand	50-56	7	100
α-helix	58-79	22
α-helix	82-84	3
α-helix	85-98	14
β-strand	106-113	8	100
β-strand	119-124	6	100
β-strand	130-133	4	100
β-strand	135-139	5	99
α-helix	142-152	11
α-helix	168-185	18
β-strand	186	1	41
β-strand	192-199	8	99
β-strand	202-209	8	99

Chain A: 12 helices, 14 β-strands

Element	Residues	Length	Sheet
α-helix	23-32	10
α-helix	33-35	3
β-strand	38-43	6	1
β-strand	47-53	7	1
β-strand	61	1	2
α-helix	63-65	3
β-strand	69-73	5	3
β-strand	76-82	7	3
α-helix	84-105	22
α-helix	108-110	3
α-helix	111-127	17
β-strand	128	1	4
β-strand	131	1	5
α-helix	132-134	3
β-strand	136-144	9	3
β-strand	148-154	7	3
β-strand	160-162	3	3
β-strand	163	1	6
β-strand	165-169	5	1
α-helix	172-184	13
α-helix	191-206	16
α-helix	212-214	3
β-strand	215-221	7	1
β-strand	228-229	2	1
α-helix	230-231	2
α-helix	232-241	10

Chains b and N: 5 helices, 14 β-strands

Element	Residues	Length	Sheet
β-strand	6-8	3	39
β-strand	11-16	6	95
β-strand	19-25	7	95
β-strand	28-30	3	39
β-strand	33-36	4	39
β-strand	42-46	5	39
β-strand	49-56	8	39
α-helix	57-77	21
α-helix	85-101	17
β-strand	108-116	9	39
β-strand	119-125	7	39
β-strand	131-133	3	39
β-strand	136-138	3	95
α-helix	142-145	4
α-helix	147-154	8
α-helix	162-179	18
β-strand	180	1	37
β-strand	186-193	8	95
β-strand	196-204	9	95

Chain B: 10 helices, 17 β-strands

Element	Residues	Length	Sheet
β-strand	8	1	10
β-strand	12	1	11
β-strand	18	1	11
α-helix	19-29	11
α-helix	32-33	2
β-strand	34-39	6	12
β-strand	42-48	7	12
β-strand	56	1	6
β-strand	65-68	4	13
β-strand	71-77	7	13
α-helix	79-100	22
α-helix	103-105	3
α-helix	106-119	14
β-strand	124	1	10
β-strand	126	1	4
α-helix	127-129	3
β-strand	131-139	9	13
β-strand	142-148	7	13
β-strand	154-156	3	13
β-strand	157	1	14
β-strand	159-162	4	12
α-helix	166-176	11
α-helix	183-197	15
β-strand	207-213	7	12
β-strand	216-219	4	12
α-helix	220-221	2
α-helix	222-230	9

Chain C: 12 helices, 13 β-strands

Element	Residues	Length	Sheet
α-helix	19-29	11
α-helix	32-33	2
β-strand	34-39	6	15
β-strand	42-48	7	15
β-strand	56	1	14
α-helix	57-59	3
β-strand	65-69	5	16
β-strand	72-78	7	16
α-helix	80-101	22
α-helix	104-106	3
α-helix	107-123	17
β-strand	124	1	17
α-helix	127-130	4
β-strand	132-140	9	16
β-strand	144-150	7	16
β-strand	156-158	3	16
β-strand	159	1	18
β-strand	161-164	4	15
α-helix	168-178	11
α-helix	186-200	15
α-helix	208-210	3
β-strand	211-219	9	15
β-strand	222-227	6	15
α-helix	228-229	2
α-helix	230-247	18

Chains d and e: 0 helices, 1 β-strand

Element	Residues	Length	Sheet
β-strand	2	1	55

Chains D and R: 11 helices, 16 β-strands

Element	Residues	Length	Sheet
β-strand	12	1	19
β-strand	18	1	19
α-helix	19-29	11
α-helix	32-33	2
β-strand	34-38	5	20
β-strand	42-48	7	20
β-strand	56	1	18
α-helix	58-61	4
β-strand	64-66	3	21
β-strand	71-77	7	21
α-helix	79-100	22
α-helix	103-105	3
α-helix	106-119	14
β-strand	123	1	22
β-strand	126	1	17
α-helix	127-129	3
β-strand	131-138	8	21
β-strand	144-149	6	21
β-strand	155-157	3	21
β-strand	158	1	23
β-strand	160-163	4	20
α-helix	167-177	11
α-helix	180-184	5
α-helix	186-198	13
β-strand	208-214	7	20
β-strand	220-221	2	20
α-helix	224-240	17

Chains E and S: 13 helices, 16 β-strands

Element	Residues	Length	Sheet
α-helix	14	1
β-strand	15	1	28
α-helix	16	1
β-strand	21	1	28
α-helix	22-31	10
α-helix	35-36	2
β-strand	37-42	6	29
β-strand	45-51	7	29
β-strand	59	1	23
α-helix	61-63	3
β-strand	67-71	5	30
β-strand	74-80	7	30
α-helix	82-103	22
α-helix	106-108	3
α-helix	109-117	9
β-strand	123	1	22
β-strand	133	1	22
β-strand	139-147	9	30
β-strand	150-156	7	30
β-strand	162-164	3	30
β-strand	165	1	31
β-strand	167-170	4	29
α-helix	174-184	11
α-helix	191-205	15
α-helix	209-210	2
β-strand	215-221	7	29
β-strand	224-228	5	29
α-helix	229-230	2
α-helix	231-239	9

13 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
Proteasome subunit alpha type-6	A, O	protein	246	Homo sapiens	P60900 (AlphaFold model)
Proteasome subunit alpha type-2	B, P	protein	234	Homo sapiens	P25787 (AlphaFold model)
Proteasome subunit alpha type-4	C, Q	protein	261	Homo sapiens	P25789 (AlphaFold model)
Isoform 3 of Proteasome subunit alpha-type 8	D, R	protein	250	Homo sapiens	Q8TAA3 (AlphaFold model)
Proteasome subunit alpha type-5	E, S	protein	241	Homo sapiens	P28066
Proteasome subunit alpha type-1	F, T	protein	263	Homo sapiens	P25786
Proteasome subunit alpha type-3	G, U	protein	255	Homo sapiens	P25788
Proteasome subunit beta type-6	H, V	protein	205	Homo sapiens	P28072
Proteasome subunit beta type-7	I, W	protein	234	Homo sapiens	Q99436
Proteasome subunit beta type-3	J, X	protein	205	Homo sapiens	P49720
Proteasome subunit beta type-2	K, Y	protein	201	Homo sapiens	P49721
Proteasome subunit beta type-1	M, a	protein	213	Homo sapiens	P20618

3 more molecules are not listed.

Sequence of entity 1 (A, O), FASTA

>9TMN_1 Proteasome subunit alpha type-6 (chains A, O)
MSRGSSAGFDRHITIFSPEGRLYQVEYAFKAINQGGLTSVAVRGKDCAVIVTQKKVPDKL
LDSSTVTHLFKITENIGCVMTGMTADSRSQVQRARYEAANWKYKYGYEIPVDMLCKRIAD
ISQVYTQNAEMRPLGCCMILIGIDEEQGPQVYKCDPAGYYCGFKATAAGVKQTESTSFLE
KKVKKKFDWTFEQTVETAITCLSTVLSIDFKPSEIEVGVVTVENPKFRILTEAEIDAHLV
ALAERD

Sequence of entity 2 (B, P), FASTA

>9TMN_2 Proteasome subunit alpha type-2 (chains B, P)
MAERGYSFSLTTFSPSGKLVQIEYALAAVAGGAPSVGIKAANGVVLATEKKQKSILYDER
SVHKVEPITKHIGLVYSGMGPDYRVLVHRARKLAQQYYLVYQEPIPTAQLVQRVASVMQE
YTQSGGVRPFGVSLLICGWNEGRPYLFQSDPSGAYFAWKATAMGKNYVNGKTFLEKRYNE
DLELEDAIHTAILTLKESFEGQMTEDNIEVGICNEAGFRRLTPTEVKDYLAAIA

Sequence of entity 3 (C, Q), FASTA

>9TMN_3 Proteasome subunit alpha type-4 (chains C, Q)
MSRRYDSRTTIFSPEGRLYQVEYAMEAIGHAGTCLGILANDGVLLAAERRNIHKLLDEVF
FSEKIYKLNEDMACSVAGITSDANVLTNELRLIAQRYLLQYQEPIPCEQLVTALCDIKQA
YTQFGGKRPFGVSLLYIGWDKHYGFQLYQSDPSGNYGGWKATCIGNNSAAAVSMLKQDYK
EGEMTLKSALALAIKVLNKTMDVSKLSAEKVEIATLTRENGKTVIRVLKQKEVEQLIKKH
EEEEAKAEREKKEKEQKEKDK

Sequence of entity 4 (D, R), FASTA

>9TMN_4 Isoform 3 of Proteasome subunit alpha-type 8 (chains D, R)
MASRYDRAITVFSPDGHLFQVEYAQEAVKKGSTAVGIRGTNIVVLGVEKKSVAKLQDERT
VRKICALDDHVCMAFAGLTADARVVINRARVECQSHKLTVEDPVTVEYITRFIATLKQKY
TQSNGRRPFGISALIVGFDDDGISRLYQTDPSGTYHAWKANAIGRSAKTVREFLEKNYTE
DAIASDSEAIKLAIKALLEVVQSGGKNIELAIIRRNQPLKMFSAKEVELYVTEIEKEKEE
AEKKKSKKSV

Sequence of entity 5 (E, S), FASTA

>9TMN_5 Proteasome subunit alpha type-5 (chains E, S)
MFLTRSEYDRGVNTFSPEGRLFQVEYAIEAIKLGSTAIGIQTSEGVCLAVEKRITSPLME
PSSIEKIVEIDAHIGCAMSGLIADAKTLIDKARVETQNHWFTYNETMTVESVTQAVSNLA
LQFGEEDADPGAMSRPFGVALLFGGVDEKGPQLFHMDPSGTFVQCDARAIGSASEGAQSS
LQEVYHKSMTLKEAIKSSLIILKQVMEEKLNATNIELATVQPGQNFHMFTKEELEEVIKD
I

Sequence of entity 6 (F, T), FASTA

>9TMN_6 Proteasome subunit alpha type-1 (chains F, T)
MFRNQYDNDVTVWSPQGRIHQIEYAMEAVKQGSATVGLKSKTHAVLVALKRAQSELAAHQ
KKILHVDNHIGISIAGLTADARLLCNFMRQECLDSRFVFDRPLPVSRLVSLIGSKTQIPT
QRYGRRPYGVGLLIAGYDDMGPHIFQTCPSANYFDCRAMSIGARSQSARTYLERHMSEFM
ECNLNELVKHGLRALRETLPAEQDLTTKNVSIGIVGKDLEFTIYDDDDVSPFLEGLEERP
QRKAQPAQPADEPAEKADEPMEH

Sequence of entity 7 (G, U), FASTA

>9TMN_7 Proteasome subunit alpha type-3 (chains G, U)
MSSIGTGYDLSASTFSPDGRVFQVEYAMKAVENSSTAIGIRCKDGVVFGVEKLVLSKLYE
EGSNKRLFNVDRHVGMAVAGLLADARSLADIAREEASNFRSNFGYNIPLKHLADRVAMYV
HAYTLYSAVRPFGCSFMLGSYSVNDGAQLYMIDPSGVSYGYWGCAIGKARQAAKTEIEKL
QMKEMTCRDIVKEVAKIIYIVHDEVKDKAFELELSWVGELTNGRHEIVPKDIREEAEKYA
KESLKEEDESDDDNM

Sequence of entity 8 (H, V), FASTA

>9TMN_8 Proteasome subunit beta type-6 (chains H, V)
TTIMAVQFDGGVVLGADSRTTTGSYIANRVTDKLTPIHDRIFCCRSGSAADTQAVADAVT
YQLGFHSIELNEPPLVHTAASLFKEMCYRYREDLMAGIIIAGWDPQEGGQVYSVPMGGMM
VRQSFAIGGSGSSYIYGYVDATYREGMTKEECLQFTANALALAMERDGSSGGVIRLAAIA
ESGVERQVLLGDQIPKFAVATLPPA

Sequence of entity 9 (I, W), FASTA

>9TMN_9 Proteasome subunit beta type-7 (chains I, W)
TTIAGVVYKDGIVLGADTRATEGMVVADKNCSKIHFISPNIYCCGAGTAADTDMTTQLIS
SNLELHSLSTGRLPRVVTANRMLKQMLFRYQGYIGAALVLGGVDVTGPHLYSIYPHGSTD
KLPYVTMGSGSLAAMAVFEDKFRPDMEEEEAKNLVSEAIAAGIFNDLGSGSNIDLCVISK
NKLDFLRPYTVPNKKGTRLGRYRCEKGTTAVLTEKITPLEIEVLEETVQTMDTS

Sequence of entity 10 (J, X), FASTA

>9TMN_10 Proteasome subunit beta type-3 (chains J, X)
MSIMSYNGGAVMAMKGKNCVAIAADRRFGIQAQMVTTDFQKIFPMGDRLYIGLAGLATDV
QTVAQRLKFRLNLYELKEGRQIKPYTLMSMVANLLYEKRFGPYYTEPVIAGLDPKTFKPF
ICSLDLIGCPMVTDDFVVSGTCAEQMYGMCESLWEPNMDPDHLFETISQAMLNAVDRDAV
SGMGVIVHIIEKDKITTRTLKARMD

Sequence of entity 11 (K, Y), FASTA

>9TMN_11 Proteasome subunit beta type-2 (chains K, Y)
MEYLIGIQGPDYVLVASDRVAASNIVQMKDDHDKMFKMSEKILLLCVGEAGDTVQFAEYI
QKNVQLYKMRNGYELSPTAAANFTRRNLADCLRSRTPYHVNLLLAGYDEHEGPALYYMDY
LAALAKAPFAAHGYGAFLTLSILDRYYTPTISRERAVELLRKCLEELQKRFILNLPTFSV
RIIDKNGIHDLDNISFPKQGS

Sequence of entity 12 (M, a), FASTA

>9TMN_12 Proteasome subunit beta type-1 (chains M, a)
RFSPYVFNGGTILAIAGEDFAIVASDTRLSEGFSIHTRDSPKCYKLTDKTVIGCSGFHGD
CLTLTKIIEARLKMYKHSNNKAMTTGAIAAMLSTILYSRRFFPYYVYNIIGGLDEEGKGA
VYSFDPVGSYQRDSFKAGGSASAMLQPLLDNQVGFKNMQNVEHVPLSLDRAMRLVKDVFI
SAAERDVYTGDALRICIVTKEGIREETVSLRKD

Ligands and cofactors

ID	Name	Formula	Copies
MG	Magnesium ion	Mg	3

Primary citation

Molecular architecture and spatial organization of proteasomes in the human sperm nucleus. Kolata, P., Dos Santos, A., Knowles, O. et al. Nat Struct Mol Biol (2026) 33:1367-1380. DOI 10.1038/s41594-026-01870-z · PubMed

Other PDB entries of the same protein (UniProt P60900 (AlphaFold model), which also has an AlphaFold model), best resolution first:

5LE5 1.8 Å, Native human 20S proteasome at 1.8 Angstrom
5LEY 1.9 Å, Human 20S proteasome complex with Oprozomib at 1.9 Angstrom
5LF4 1.99 Å, Human 20S proteasome complex with Delanzomib at 2.0 Angstrom
5LF1 2.0 Å, Human 20S proteasome complex with Dihydroeponemycin at 2.0 Angstrom
5LF7 2.0 Å, Human 20S proteasome complex with Ixazomib at 2.0 Angstrom
8UD9 2.04 Å, Structure of human constitutive 20S proteasome complexed with the inhibitor TDI-8304
5LF6 2.07 Å, Human 20S proteasome complex with Z-LLY-ketoaldehyde at 2.1 Angstrom
5LF3 2.1 Å, Human 20S proteasome complex with Bortezomib at 2.1 Angstrom
8BZL 2.14 Å, Human 20S Proteasome in complex with peptide activator peptide BLM42
5LEZ 2.19 Å, Human 20S proteasome complex with Oprozomib in Mg-Acetate at 2.2 Angstrom
5LEX 2.2 Å, Native human 20S proteasome in Mg-Acetate at 2.2 Angstrom
7AWE 2.29 Å, HUMAN IMMUNOPROTEASOME 20S PARTICLE IN COMPLEX WITH [(1R)-2-(1-benzofuran-3-yl)-1-{[(1S,2…

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