9RLT: Proteasome subunit alpha type-1

dimerised 13S-13S+Beta5 proteasome precursor complexes. Determined by electron microscopy at 3.09 Å resolution. Released 18 Mar 2026.

Method: Electron microscopy
Resolution: 3.09 Å
Organism: Saccharomyces cerevisiae
Chains: 27
Atoms: 47,532
Mol. weight: 735.41 kDa
Released: 18 Mar 2026

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

Secondary structure: helices and β-sheets

9RLT contains 244 α-helices and 331 β-strands across 27 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 3: 8 helices, 0 β-strands

Element	Residues	Length
α-helix	-10--5	6
α-helix	54-58	5
α-helix	61-76	16
α-helix	79-93	15
α-helix	103-104	2
α-helix	105-110	6
α-helix	119-122	4
α-helix	139-146	8

Chain 4: 12 helices, 15 β-strands

Element	Residues	Length	Sheet
α-helix	10-12	3
α-helix	18-20	3
α-helix	30-34	5
β-strand	35-37	3	83
α-helix	44-46	3
β-strand	49-54	6	83
α-helix	55-60	6
α-helix	63-66	4
β-strand	69-77	9	83
β-strand	79-80	2	84
α-helix	96-99	4
β-strand	103	1	11
β-strand	116-117	2	84
β-strand	120-127	8	83
β-strand	130-135	6	83
α-helix	136	1
α-helix	144-160	17
β-strand	164-171	8	83
β-strand	178-181	4	83
β-strand	193-194	2	85
α-helix	196-206	11
β-strand	214-220	7	83
β-strand	222	1	86
β-strand	229	1	86
α-helix	232-246	15
α-helix	250-262	13
β-strand	275	1	21

Chain 5: 14 helices, 22 β-strands

Element	Residues	Length	Sheet
β-strand	3-6	4	4
α-helix	11-13	3
α-helix	14-25	12
β-strand	31-35	5	4
α-helix	36-37	2
β-strand	41	1	5
β-strand	44-45	2	85
β-strand	46	1	6
β-strand	51	1	7
α-helix	55-57	3
β-strand	67	1	6
β-strand	70-75	6	4
β-strand	80-85	6	4
β-strand	89	1	5
α-helix	94-100	7
α-helix	103-110	8
β-strand	114-118	5	4
β-strand	121	1	8
β-strand	131	1	9
β-strand	138-144	7	4
α-helix	146-148	3
α-helix	149-152	4
β-strand	165	1	10
β-strand	169-170	2	4
β-strand	176	1	9
β-strand	179	1	10
α-helix	184-193	10
β-strand	204-210	7	4
β-strand	211	1	8
α-helix	218-230	13
α-helix	237-239	3
α-helix	244-245	2
β-strand	246	1	7
α-helix	248-251	4
α-helix	259-261	3
β-strand	266	1	32

Chain 6: 9 helices, 2 β-strands

Element	Residues	Length	Sheet
β-strand	22	1	55
β-strand	30	1	55
α-helix	32-35	4
α-helix	45-47	3
α-helix	54-58	5
α-helix	60-76	17
α-helix	79-93	15
α-helix	103-104	2
α-helix	105-110	6
α-helix	119-122	4
α-helix	139-146	8

Chain 7: 13 helices, 12 β-strands

Element	Residues	Length	Sheet
α-helix	10-12	3
α-helix	18-20	3
α-helix	30-34	5
β-strand	35-37	3	74
α-helix	44-46	3
β-strand	49-54	6	74
α-helix	55-57	3
α-helix	63-66	4
β-strand	69-80	12	74
α-helix	96-99	4
α-helix	106-109	4
β-strand	116-126	11	74
β-strand	130-135	6	74
α-helix	144-158	15
β-strand	164-171	8	74
β-strand	178-180	3	74
β-strand	193-194	2	75
α-helix	196-203	8
β-strand	214-220	7	74
β-strand	221-222	2	76
β-strand	229-230	2	76
α-helix	232-246	15
α-helix	252-262	11
α-helix	271-274	4
β-strand	275	1	53

Chain 8: 14 helices, 20 β-strands

Element	Residues	Length	Sheet
β-strand	3-7	5	77
α-helix	11-13	3
α-helix	14-25	12
β-strand	30-35	6	77
β-strand	41	1	78
β-strand	44-45	2	75
β-strand	46	1	79
β-strand	51	1	80
α-helix	55-57	3
β-strand	67	1	79
β-strand	70-75	6	77
β-strand	80-85	6	77
β-strand	89	1	78
α-helix	92-94	3
α-helix	95-97	3
α-helix	98-102	5
α-helix	103-110	8
β-strand	114-121	8	77
α-helix	123-125	3
β-strand	131	1	81
β-strand	138-144	7	77
α-helix	146-148	3
α-helix	149-153	5
β-strand	164-165	2	82
β-strand	169-170	2	77
β-strand	176	1	81
β-strand	179-180	2	82
α-helix	184-193	10
β-strand	204-211	8	77
α-helix	220-230	11
α-helix	237-239	3
β-strand	246	1	80
α-helix	247-251	5
β-strand	266	1	65

Chain A: 8 helices, 11 β-strands

Element	Residues	Length	Sheet
α-helix	26-35	10
β-strand	42-46	5	1
β-strand	50-55	6	1
α-helix	66-68	3
β-strand	72-74	3	2
β-strand	79-84	6	2
α-helix	87-108	22
α-helix	111-113	3
α-helix	114-130	17
β-strand	131	1	3
β-strand	140-147	8	2
β-strand	151-157	7	2
β-strand	163-166	4	2
β-strand	168-171	4	1
α-helix	175-189	15
α-helix	199-214	16
β-strand	224-229	6	1
β-strand	232-235	4	1
α-helix	238-245	8

Chain B: 11 helices, 16 β-strands

Element	Residues	Length	Sheet
β-strand	12	1	23
β-strand	18	1	23
α-helix	19-28	10
β-strand	34-39	6	24
β-strand	42-48	7	24
β-strand	56	1	2
α-helix	58-60	3
β-strand	65-68	4	25
β-strand	71-77	7	25
α-helix	79-92	14
α-helix	93-98	6
α-helix	99-101	3
α-helix	107-119	13
α-helix	120-122	3
β-strand	127	1	3
β-strand	132-140	9	25
β-strand	144-150	7	25
β-strand	156-158	3	25
β-strand	159	1	26
β-strand	161-164	4	24
α-helix	168-176	9
α-helix	185-199	15
β-strand	209-214	6	24
α-helix	219-221	3
β-strand	224-225	2	27
β-strand	235-237	3	24
α-helix	240-248	9

19 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-1	A, O	protein	252	Saccharomyces cerevisiae	P21243 (AlphaFold model)
Proteasome subunit alpha type-4	D, R	protein	254	Saccharomyces cerevisiae	P40303 (AlphaFold model)
Proteasome subunit alpha type-5	E, S	protein	260	Saccharomyces cerevisiae	P32379 (AlphaFold model)
Proteasome subunit alpha type-6	F, T	protein	234	Saccharomyces cerevisiae	P40302 (AlphaFold model)
Proteasome maturation factor UMP1	3, 6	protein	162	Saccharomyces cerevisiae	P38293
Proteasome subunit alpha type-2	B, P	protein	250	Saccharomyces cerevisiae	P23639
Proteasome subunit alpha type-3	C, Q	protein	258	Saccharomyces cerevisiae	P23638
Probable proteasome subunit alpha type-7	G, U	protein	288	Saccharomyces cerevisiae	P21242
Proteasome subunit beta type-2	I, W	protein	261	Saccharomyces cerevisiae	P25043
Proteasome subunit beta type-3	J, X	protein	205	Saccharomyces cerevisiae	P25451
Proteasome subunit beta type-4	K, Y	protein	198	Saccharomyces cerevisiae	P22141
Proteasome subunit beta type-5	Z	protein	287	Saccharomyces cerevisiae	P30656

2 more molecules are not listed.

Sequence of entity 1 (A, O), FASTA

>9RLT_1 Proteasome subunit alpha type-1 (chains A, O)
MSGAAAASAAGYDRHITIFSPEGRLYQVEYAFKATNQTNINSLAVRGKDCTVVISQKKVP
DKLLDPTTVSYIFCISRTIGMVVNGPIPDARNAALRAKAEAAEFRYKYGYDMPCDVLAKR
MANLSQIYTQRAYMRPLGVILTFVSVDEELGPSIYKTDPAGYYVGYKATATGPKQQEITT
NLENHFKKSKIDHINEESWEKVVEFAITHMIDALGTEFSKNDLEVGVATKDKFFTLSAEN
IEERLVAIAEQD

Sequence of entity 2 (D, R), FASTA

>9RLT_2 Proteasome subunit alpha type-4 (chains D, R)
MSGYDRALSIFSPDGHIFQVEYALEAVKRGTCAVGVKGKNCVVLGCERRSTLKLQDTRIT
PSKVSKIDSHVVLSFSGLNADSRILIEKARVEAQSHRLTLEDPVTVEYLTRYVAGVQQRY
TQSGGVRPFGVSTLIAGFDPRDDEPKLYQTEPSGIYSSWSAQTIGRNSKTVREFLEKNYD
RKEPPATVEECVKLTVRSLLEVVQTGAKNIEITVVKPDSDIVALSSEEINQYVTQIEQEK
QEQQEQDKKKKSNH

Sequence of entity 3 (E, S), FASTA

>9RLT_3 Proteasome subunit alpha type-5 (chains E, S)
MFLTRSEYDRGVSTFSPEGRLFQVEYSLEAIKLGSTAIGIATKEGVVLGVEKRATSPLLE
SDSIEKIVEIDRHIGCAMSGLTADARSMIEHARTAAVTHNLYYDEDINVESLTQSVCDLA
LRFGEGASGEERLMSRPFGVALLIAGHDADDGYQLFHAEPSGTFYRYNAKAIGSGSEGAQ
AELLNEWHSSLTLKEAELLVLKILKQVMEEKLDENNAQLSCITKQDGFKIYDNEKTAELI
KELKEKEAAESPEEADVEMS

Sequence of entity 4 (F, T), FASTA

>9RLT_4 Proteasome subunit alpha type-6 (chains F, T)
MFRNNYDGDTVTFSPTGRLFQVEYALEAIKQGSVTVGLRSNTHAVLVALKRNADELSSYQ
KKIIKCDEHMGLSLAGLAPDARVLSNYLRQQCNYSSLVFNRKLAVERAGHLLCDKAQKNT
QSYGGRPYGVGLLIIGYDKSGAHLLEFQPSGNVTELYGTAIGARSQGAKTYLERTLDTFI
KIDGNPDELIKAGVEAISQSLRDESLTVDNLSIAIVGKDTPFTIYDGEAVAKYI

Sequence of entity 5 (3, 6), FASTA

>9RLT_5 Proteasome maturation factor UMP1 (chains 3, 6)
DYKDDDDKHHHHHHMNIVPQDTFKSQVSTDQDKSVLSSAVPSLPDTLRQQEGGAVPLSTQ
LNDRHPLESTLKNWETTQRQRQMEQYRQIFGIAEPMKRTMEMEIVNRTDFNPLSTNGSIH
RDILLNKECSIDWEDVYPGTGLQASTMVGDDVHSKIEKQLGI

Sequence of entity 6 (B, P), FASTA

>9RLT_6 Proteasome subunit alpha type-2 (chains B, P)
MTDRYSFSLTTFSPSGKLGQIDYALTAVKQGVTSLGIKATNGVVIATEKKSSSPLAMSET
LSKVSLLTPDIGAVYSGMGPDYRVLVDKSRKVAHTSYKRIYGEYPPTKLLVSEVAKIMQE
ATQSGGVRPFGVSLLIAGHDEFNGFSLYQVDPSGSYFPWKATAIGKGSVAAKTFLEKRWN
DELELEDAIHIALLTLKESVEGEFNGDTIELAIIGDENPDLLGYTGIPTDKGPRFRKLTS
QEINDRLEAL

Sequence of entity 7 (C, Q), FASTA

>9RLT_7 Proteasome subunit alpha type-3 (chains C, Q)
MGSRRYDSRTTIFSPEGRLYQVEYALESISHAGTAIGIMASDGIVLAAERKVTSTLLEQD
TSTEKLYKLNDKIAVAVAGLTADAEILINTARIHAQNYLKTYNEDIPVEILVRRLSDIKQ
GYTQHGGLRPFGVSFIYAGYDDRYGYQLYTSNPSGNYTGWKAISVGANTSAAQTLLQMDY
KDDMKVDDAIELALKTLSKTTDSSALTYDRLEFATIRKGANDGEVYQKIFKPQEIKDILV
KTGITKKDEDEEADEDMK

Sequence of entity 8 (G, U), FASTA

>9RLT_8 Probable proteasome subunit alpha type-7 (chains G, U)
MTSIGTGYDLSNSVFSPDGRNFQVEYAVKAVENGTTSIGIKCNDGVVFAVEKLITSKLLV
PQKNVKIQVVDRHIGCVYSGLIPDGRHLVNRGREEAASFKKLYKTPIPIPAFADRLGQYV
QAHTLYNSVRPFGVSTIFGGVDKNGAHLYMLEPSGSYWGYKGAATGKGRQSAKAELEKLV
DHHPEGLSAREAVKQAAKIIYLAHEDNKEKDFELEISWCSLSETNGLHKFVKGDLLQEAI
DFAQKEINGDDDEDEDDSDNVMSSDDENAPVATNANATTDQEGDIHLE

Sequence of entity 9 (I, W), FASTA

>9RLT_9 Proteasome subunit beta type-2 (chains I, W)
MAGLSFDNYQRNNFLAENSHTQPKATSTGTTIVGVKFNNGVVIAADTRSTQGPIVADKNC
AKLHRISPKIWCAGAGTAADTEAVTQLIGSNIELHSLYTSREPRVVSALQMLKQHLFKYQ
GHIGAYLIVAGVDPTGSHLFSIHAHGSTDVGYYLSLGSGSLAAMAVLESHWKQDLTKEEA
IKLASDAIQAGIWNDLGSGSNVDVCVMEIGKDAEYLRNYLTPNVREEKQKSYKFPRGTTA
VLKESIVNICDIQEEQVDITA

Sequence of entity 10 (J, X), FASTA

>9RLT_10 Proteasome subunit beta type-3 (chains J, X)
MSDPSSINGGIVVAMTGKDCVAIACDLRLGSQSLGVSNKFEKIFHYGHVFLGITGLATDV
TTLNEMFRYKTNLYKLKEERAIEPETFTQLVSSSLYERRFGPYFVGPVVAGINSKSGKPF
IAGFDLIGCIDEAKDFIVSGTASDQLFGMCESLYEPNLEPEDLFETISQALLNAADRDAL
SGWGAVVYIIKKDEVVKRYLKMRQD

Sequence of entity 11 (K, Y), FASTA

>9RLT_11 Proteasome subunit beta type-4 (chains K, Y)
MDIILGIRVQDSVILASSKAVTRGISVLKDSDDKTRQLSPHTLMSFAGEAGDTVQFAEYI
QANIQLYSIREDYELSPQAVSSFVRQELAKSIRSRRPYQVNVLIGGYDKKKNKPELYQID
YLGTKVELPYGAHGYSGFYTFSLLDHHYRPDMTTEEGLDLLKLCVQELEKRMPMDFKGVI
VKIVDKDGIRQVDDFQAQ

Sequence of entity 12 (Z), FASTA

>9RLT_12 Proteasome subunit beta type-5 (chains Z)
MQAIADSFSVPNRLVKELQYDNEQNLESDFVTGASQFQRLAPSLTVPPIASPQQFLRAHT
DDSRNPDCKIKIAHGTTTLAFRFQGGIIVAVDSRATAGNWVASQTVKKVIEINPFLLGTM
AGGAADCQFWETWLGSQCRLHELREKERISVAAASKILSNLVYQYKGAGLSMGTMICGYT
RKEGPTIYYVDSDGTRLKGDIFCVGSGQTFAYGVLDSNYKWDLSVEDALYLGKRSILAAA
HRDAYSGGSVNLYHVTEDGWIYHGNHDVGELFWKVKEEEGSFNNVIG

Primary citation

Structural transitions in the stepwise assembly of proteasome core particles. Mark, E., Ramos, P.C., Nunes, M.M. et al. Nat Commun (2026) 17. DOI 10.1038/s41467-026-70525-w · PubMed

Other PDB entries of the same protein (UniProt P21243 (AlphaFold model), which also has an AlphaFold model), best resolution first:

1RYP 1.9 Å, Crystal structure of the 20S proteasome from yeast at 2.4 Å resolution
8RVQ 2.02 Å, 20S proteasome from pre1-1
4R17 2.1 Å, Ligand-induced aziridine-formation at subunit beta5 of the yeast 20S proteasome
8RVL 2.14 Å, Proteasomal late precursor complex from pre1-1
8U7U 2.16 Å, Proteasome 20S Core Particle from Beta 3 D205 deletion
1G65 2.25 Å, Crystal structure of epoxomicin:20s proteasome reveals a molecular basis for selectivity…
8RVP 2.28 Å, Proteasomal late precursor complex from pre1-1, state 2
4QVP 2.3 Å, yCP beta5-M45T mutant in complex with bortezomib
5CZ4 2.3 Å, Yeast 20S proteasome at 2.3 A resolution
6HWE 2.3 Å, Yeast 20S proteasome beta2-G45A mutant in complex with carfilzomib
9GBK 2.39 Å, Blm10-20S proteasome complex from pre1-1
1G0U 2.4 Å, A gated channel into the proteasome core particle

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