9K50: 26S proteasome regulatory subunit 7

Structure of substrate-engaged human 26S proteasome RP-CP subcomplex in state ED1.2. Determined by electron microscopy at 3.2 Å resolution. Released 29 Apr 2026.

Method: Electron microscopy
Resolution: 3.2 Å
Organisms: Homo sapiens, Saccharomyces cerevisiae
Chains: 47
Atoms: 106,307
Mol. weight: 1669.54 kDa
Ligands: ZN, ADP, MG, ATP
Released: 29 Apr 2026

Explore 9K50 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9K50 contains 584 α-helices and 551 β-strands across 47 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: 20 helices, 3 β-strands

Element	Residues	Length	Sheet
α-helix	5-10	6
α-helix	18-30	13
α-helix	36-46	11
α-helix	54-66	13
α-helix	73-87	15
α-helix	90-103	14
α-helix	111-122	12
α-helix	131-141	11
α-helix	150-161	12
α-helix	170-182	13
α-helix	190-206	17
α-helix	220-226	7
α-helix	231-242	12
α-helix	247-256	10
α-helix	265-275	11
α-helix	277-283	7
β-strand	291-292	2	6
α-helix	293-299	7
α-helix	307-317	11
β-strand	323-325	3	6
β-strand	330-332	3	6
α-helix	343-370	28
α-helix	372-375	4

Chain A: 17 helices, 15 β-strands

Element	Residues	Length	Sheet
α-helix	27-35	9
α-helix	42-63	22
α-helix	72-74	3
α-helix	87-90	4
β-strand	97-99	3	1
β-strand	100-103	4	2
β-strand	111-114	4	2
β-strand	120-123	4	2
β-strand	125	1	1
β-strand	140-142	3	1
β-strand	149-152	4	1
α-helix	162-164	3
α-helix	174-177	4
α-helix	181-192	12
α-helix	199-203	5
β-strand	212-215	4	3
α-helix	222-231	10
β-strand	236-240	5	3
α-helix	242-244	3
α-helix	250-263	14
β-strand	270-275	6	3
α-helix	277-283	7
α-helix	292-308	17
β-strand	317-320	4	3
β-strand	339-342	4	3
α-helix	349-359	11
β-strand	364	1	4
α-helix	370-375	6
α-helix	382-398	17
β-strand	404	1	4
α-helix	406-416	11
β-strand	432	1	5

Chain b: 7 helices, 10 β-strands

Element	Residues	Length	Sheet
β-strand	4-10	7	12
β-strand	13	1	13
α-helix	14-16	3
α-helix	25-43	19
β-strand	48-53	6	12
β-strand	55	1	14
β-strand	62-65	4	12
α-helix	69-75	7
β-strand	82	1	13
β-strand	84	1	14
α-helix	87-96	10
β-strand	106-113	8	12
α-helix	121-132	12
β-strand	137-142	6	12
α-helix	151-160	10
β-strand	171	1	12
α-helix	182-185	4

Chain B: 19 helices, 19 β-strands

Element	Residues	Length	Sheet
α-helix	36-38	3
α-helix	59-82	24
α-helix	94-102	9
α-helix	107	1
β-strand	108-112	5	1
β-strand	117	1	7
β-strand	120	1	7
β-strand	123-124	2	1
β-strand	130-131	2	1
β-strand	134	1	7
β-strand	135	1	8
β-strand	149-152	4	1
β-strand	159	1	8
β-strand	161-162	2	1
α-helix	169-173	5
β-strand	175	1	9
α-helix	184-186	3
α-helix	191-206	16
α-helix	210-214	5
α-helix	217-219	3
β-strand	221-225	5	9
α-helix	232-241	10
β-strand	247-251	5	9
α-helix	252-255	4
α-helix	262-276	15
β-strand	281-285	5	9
α-helix	287-289	3
α-helix	303-316	14
β-strand	326-330	5	9
α-helix	339-342	4
β-strand	349-352	4	9
α-helix	360-368	9
β-strand	374	1	10
α-helix	380-386	7
α-helix	392-408	17
β-strand	414	1	10
α-helix	416-426	11
β-strand	439	1	11

Chain c: 13 helices, 9 β-strands

Element	Residues	Length	Sheet
β-strand	31-33	3	18
α-helix	35-47	13
α-helix	49-51	3
β-strand	54-60	7	18
β-strand	67-73	7	18
α-helix	84-86	3
α-helix	89-100	12
β-strand	107-114	8	18
α-helix	124-136	13
β-strand	141-145	5	18
β-strand	157-162	6	18
α-helix	163-164	2
α-helix	189-192	4
β-strand	196	1	18
β-strand	200-203	4	18
β-strand	205-207	3	18
α-helix	214-221	8
α-helix	227-229	3
α-helix	237-261	25
α-helix	267-273	7
α-helix	279-282	4
α-helix	285-308	24

Chain C: 15 helices, 12 β-strands

Element	Residues	Length	Sheet
α-helix	12-19	8
α-helix	21-66	46
α-helix	69-70	2
β-strand	71-81	11	1
β-strand	84-87	4	1
β-strand	95-99	5	1
β-strand	112-116	5	1
β-strand	122-126	5	1
α-helix	155-170	16
α-helix	172-178	7
α-helix	181-183	3
β-strand	185-189	5	15
α-helix	198-205	8
β-strand	210-214	5	15
β-strand	223	1	16
α-helix	226-240	15
β-strand	244-249	6	15
α-helix	269-280	12
β-strand	289-294	6	15
α-helix	298-300	3
β-strand	313-316	4	15
α-helix	318-320	3
α-helix	322-332	11
α-helix	344-349	6
α-helix	357-371	15
α-helix	380-390	11
β-strand	405	1	17

Chain d: 14 helices, 3 β-strands

Element	Residues	Length	Sheet
α-helix	17-30	14
α-helix	46-65	20
α-helix	68-81	14
α-helix	95-108	14
α-helix	112-118	7
α-helix	119-121	3
α-helix	131-144	14
α-helix	148-153	6
α-helix	154-156	3
α-helix	164-182	19
β-strand	188-189	2	23
α-helix	191-193	3
α-helix	194-198	5
α-helix	205-212	8
β-strand	216-217	2	23
β-strand	222-223	2	23
α-helix	240-253	14

Chain D: 16 helices, 15 β-strands

Element	Residues	Length	Sheet
α-helix	40-80	41
β-strand	88-97	10	1
β-strand	100-105	6	1
β-strand	106	1	19
β-strand	108	1	19
β-strand	111-114	4	1
α-helix	121-123	3
β-strand	129-132	4	1
β-strand	139-142	4	1
α-helix	143-144	2
α-helix	164-166	3
α-helix	171-177	7
α-helix	178-182	5
α-helix	183-186	4
α-helix	188-194	7
β-strand	201-205	5	20
α-helix	213-221	9
β-strand	226-230	5	20
β-strand	239	1	21
α-helix	242-256	15
β-strand	260-264	5	20
α-helix	269-271	3
β-strand	272	1	22
α-helix	283-296	14
β-strand	305-311	7	20
β-strand	317	1	22
β-strand	329-332	4	20
α-helix	341-349	9
α-helix	361-364	4
α-helix	372-388	17
α-helix	398-407	10

39 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
26S proteasome regulatory subunit 7	A	protein	433	Homo sapiens	P35998 (AlphaFold model)
26S proteasome regulatory subunit 4	B	protein	440	Homo sapiens	P62191 (AlphaFold model)
26S proteasome regulatory subunit 8	C	protein	398	Homo sapiens	P62195 (AlphaFold model)
26S proteasome regulatory subunit 6B	D	protein	418	Homo sapiens	P43686 (AlphaFold model)
Proteasome 26S subunit, ATPase 6	E	protein	403	Homo sapiens	A0A087X2I1
26S proteasome regulatory subunit 6A	F	protein	439	Homo sapiens	P17980
Proteasome subunit alpha type-6	G, g	protein	246	Homo sapiens	P60900
Proteasome subunit alpha type-2	H, h	protein	234	Homo sapiens	P25787
Proteasome subunit alpha type-4	I, i	protein	261	Homo sapiens	P25789
Proteasome subunit alpha type-7	J, j	protein	248	Homo sapiens	O14818
Proteasome subunit alpha type-5	K, k	protein	241	Homo sapiens	P28066
Proteasome subunit alpha type-1	L, l	protein	263	Homo sapiens	P25786

21 more molecules are not listed.

Sequence of entity 1 (A), FASTA

>9K50_1 26S proteasome regulatory subunit 7 (chains A)
MPDYLGADQRKTKEDEKDDKPIRALDEGDIALLKTYGQSTYSRQIKQVEDDIQQLLKKIN
ELTGIKESDTGLAPPALWDLAADKQTLQSEQPLQVARCTKIINADSEDPKYIINVKQFAK
FVVDLSDQVAPTDIEEGMRVGVDRNKYQIHIPLPPKIDPTVTMMQVEEKPDVTYSDVGGC
KEQIEKLREVVETPLLHPERFVNLGIEPPKGVLLFGPPGTGKTLCARAVANRTDACFIRV
IGSELVQKYVGEGARMVRELFEMARTKKACLIFFDEIDAIGGARFDDGAGGDNEVQRTML
ELINQLDGFDPRGNIKVLMATNRPDTLDPALMRPGRLDRKIEFSLPDLEGRTHIFKIHAR
SMSVERDIRFELLARLCPNSTGAEIRSVCTEAGMFAIRARRKIATEKDFLEAVNKVIKSY
AKFSATPRYMTYN

Sequence of entity 2 (B), FASTA

>9K50_2 26S proteasome regulatory subunit 4 (chains B)
MGQSQSGGHGPGGGKKDDKDKKKKYEPPVPTRVGKKKKKTKGPDAASKLPLVTPHTQCRL
KLLKLERIKDYLLMEEEFIRNQEQMKPLEEKQEEERSKVDDLRGTPMSVGTLEEIIDDNH
AIVSTSVGSEHYVSILSFVDKDLLEPGCSVLLNHKVHAVIGVLMDDTDPLVTVMKVEKAP
QETYADIGGLDNQIQEIKESVELPLTHPEYYEEMGIKPPKGVILYGPPGTGKTLLAKAVA
NQTSATFLRVVGSELIQKYLGDGPKLVRELFRVAEEHAPSIVFIDEIDAIGTKRYDSNSG
GEREIQRTMLELLNQLDGFDSRGDVKVIMATNRIETLDPALIRPGRIDRKIEFPLPDEKT
KKRIFQIHTSRMTLADDVTLDDLIMAKDDLSGADIKAICTEAGLMALRERRMKVTNEDFK
KSKENVLYKKQEGTPEGLYL

Sequence of entity 3 (C), FASTA

>9K50_3 26S proteasome regulatory subunit 8 (chains C)
MELEEGKAGSGLRQYYLSKIEELQLIVNDKSQNLRRLQAQRNELNAKVRLLREELQLLQE
QGSYVGEVVRAMDKKKVLVKVHPEGKFVVDVDKNIDINDVTPNCRVALRNDSYTLHKILP
NKVDPLVSLMMVEKVPDSTYEMIGGLDKQIKEIKEVIELPVKHPELFEALGIAQPKGVLL
YGPPGTGKTLLARAVAHHTDCTFIRVSGSELVQKFIGEGARMVRELFVMAREHAPSIIFM
DEIDSIGSSRLEGGSGGDSEVQRTMLELLNQLDGFEATKNIKVIMATNRIDILDSALLRP
GRIDRKIEFPPPNEEARLDILKIHSRKMNLTRGINLRKIAELMPGASGAEVKGVCTEAGM
YALRERRVHVTQEDFEMAVAKVMQKDSEKNMSIKKLWK

Sequence of entity 4 (D), FASTA

>9K50_4 26S proteasome regulatory subunit 6B (chains D)
MEEIGILVEKAQDEIPALSVSRPQTGLSFLGPEPEDLEDLYSRYKKLQQELEFLEVQEEY
IKDEQKNLKKEFLHAQEEVKRIQSIPLVIGQFLEAVDQNTAIVGSTTGSNYYVRILSTID
RELLKPNASVALHKHSNALVDVLPPEADSSIMMLTSDQKPDVMYADIGGMDIQKQEVREA
VELPLTHFELYKQIGIDPPRGVLMYGPPGCGKTMLAKAVAHHTTAAFIRVVGSEFVQKYL
GEGPRMVRDVFRLAKENAPAIIFIDEIDAIATKRFDAQTGADREVQRILLELLNQMDGFD
QNVNVKVIMATNRADTLDPALLRPGRLDRKIEFPLPDRRQKRLIFSTITSKMNLSEEVDL
EDYVARPDKISGADINSICQESGMLAVRENRYIVLAKDFEKAYKTVIKKDEQEHEFYK

Sequence of entity 5 (E), FASTA

>9K50_5 Proteasome 26S subunit, ATPase 6 (chains E)
MAIPGIPYERRLLIMADPRDKALQDYRKKLLEHKEIDGRLKELREQLKELTKQYEKSEND
LKALQSVGQIVGEVLKQLTEEKFIVKATNGPRYVVGCRRQLDKSKLKPGTRVALDMTTLT
IMRYLPREVDPLVYNMSHEDPGNVSYSEIGGLSEQIRELREVIELPLTNPELFQRVGIIP
PKGCLLYGPPGTGKTLLARAVASQLDCNFLKVVSSSIVDKYIGESARLIREMFNYARDHQ
PCIIFMDEIDAIGGRRFSEGTSADREIQRTLMELLNQMDGFDTLHRVKMIMATNRPDTLD
PALLRPGRLDRKIHIDLPNEQARLDILKIHAGPITKHGEIDYEAIVKLSDGFNGADLRNV
CTEAGMFAIRADHDFVVQEDFMKAVRKVADSKKLESKLDYKPV

Sequence of entity 6 (F), FASTA

>9K50_6 26S proteasome regulatory subunit 6A (chains F)
MNLLPNIESPVTRQEKMATVWDEAEQDGIGEEVLKMSTEEIIQRTRLLDSEIKIMKSEVL
RVTHELQAMKDKIKENSEKIKVNKTLPYLVSNVIELLDVDPNDQEEDGANIDLDSQRKGK
CAVIKTSTRQTYFLPVIGLVDAEKLKPGDLVGVNKDSYLILETLPTEYDSRVKAMEVDER
PTEQYSDIGGLDKQIQELVEAIVLPMNHKEKFENLGIQPPKGVLMYGPPGTGKTLLARAC
AAQTKATFLKLAGPQLVQMFIGDGAKLVRDAFALAKEKAPSIIFIDELDAIGTKRFDSEK
AGDREVQRTMLELLNQLDGFQPNTQVKVIAATNRVDILDPALLRSGRLDRKIEFPMPNEE
ARARIMQIHSRKMNVSPDVNYEELARCTDDFNGAQCKAVCVEAGMIALRRGATELTHEDY
MEGILEVQAKKKANLQYYA

Sequence of entity 7 (G, g), FASTA

>9K50_7 Proteasome subunit alpha type-6 (chains G, g)
MSRGSSAGFDRHITIFSPEGRLYQVEYAFKAINQGGLTSVAVRGKDCAVIVTQKKVPDKL
LDSSTVTHLFKITENIGCVMTGMTADSRSQVQRARYEAANWKYKYGYEIPVDMLCKRIAD
ISQVYTQNAEMRPLGCCMILIGIDEEQGPQVYKCDPAGYYCGFKATAAGVKQTESTSFLE
KKVKKKFDWTFEQTVETAITCLSTVLSIDFKPSEIEVGVVTVENPKFRILTEAEIDAHLV
ALAERD

Sequence of entity 8 (H, h), FASTA

>9K50_8 Proteasome subunit alpha type-2 (chains H, h)
MAERGYSFSLTTFSPSGKLVQIEYALAAVAGGAPSVGIKAANGVVLATEKKQKSILYDER
SVHKVEPITKHIGLVYSGMGPDYRVLVHRARKLAQQYYLVYQEPIPTAQLVQRVASVMQE
YTQSGGVRPFGVSLLICGWNEGRPYLFQSDPSGAYFAWKATAMGKNYVNGKTFLEKRYNE
DLELEDAIHTAILTLKESFEGQMTEDNIEVGICNEAGFRRLTPTEVKDYLAAIA

Sequence of entity 9 (I, i), FASTA

>9K50_9 Proteasome subunit alpha type-4 (chains I, i)
MSRRYDSRTTIFSPEGRLYQVEYAMEAIGHAGTCLGILANDGVLLAAERRNIHKLLDEVF
FSEKIYKLNEDMACSVAGITSDANVLTNELRLIAQRYLLQYQEPIPCEQLVTALCDIKQA
YTQFGGKRPFGVSLLYIGWDKHYGFQLYQSDPSGNYGGWKATCIGNNSAAAVSMLKQDYK
EGEMTLKSALALAIKVLNKTMDVSKLSAEKVEIATLTRENGKTVIRVLKQKEVEQLIKKH
EEEEAKAEREKKEKEQKEKDK

Sequence of entity 10 (J, j), FASTA

>9K50_10 Proteasome subunit alpha type-7 (chains J, j)
MSYDRAITVFSPDGHLFQVEYAQEAVKKGSTAVGVRGRDIVVLGVEKKSVAKLQDERTVR
KICALDDNVCMAFAGLTADARIVINRARVECQSHRLTVEDPVTVEYITRYIASLKQRYTQ
SNGRRPFGISALIVGFDFDGTPRLYQTDPSGTYHAWKANAIGRGAKSVREFLEKNYTDEA
IETDDLTIKLVIKALLEVVQSGGKNIELAVMRRDQSLKILNPEEIEKYVAEIEKEKEENE
KKKQKKAS

Sequence of entity 11 (K, k), FASTA

>9K50_11 Proteasome subunit alpha type-5 (chains K, k)
MFLTRSEYDRGVNTFSPEGRLFQVEYAIEAIKLGSTAIGIQTSEGVCLAVEKRITSPLME
PSSIEKIVEIDAHIGCAMSGLIADAKTLIDKARVETQNHWFTYNETMTVESVTQAVSNLA
LQFGEEDADPGAMSRPFGVALLFGGVDEKGPQLFHMDPSGTFVQCDARAIGSASEGAQSS
LQEVYHKSMTLKEAIKSSLIILKQVMEEKLNATNIELATVQPGQNFHMFTKEELEEVIKD
I

Sequence of entity 12 (L, l), FASTA

>9K50_12 Proteasome subunit alpha type-1 (chains L, l)
MFRNQYDNDVTVWSPQGRIHQIEYAMEAVKQGSATVGLKSKTHAVLVALKRAQSELAAHQ
KKILHVDNHIGISIAGLTADARLLCNFMRQECLDSRFVFDRPLPVSRLVSLIGSKTQIPT
QRYGRRPYGVGLLIAGYDDMGPHIFQTCPSANYFDCRAMSIGARSQSARTYLERHMSEFM
ECNLNELVKHGLRALRETLPAEQDLTTKNVSIGIVGKDLEFTIYDDDDVSPFLEGLEERP
QRKAQPAQPADEPAEKADEPMEH

Ligands and cofactors

ID	Name	Formula	Copies
ZN	Zinc ion	Zn	1
ADP	Adenosine-5'-diphosphate	C10 H15 N5 O10 P2	1
MG	Magnesium ion	Mg	4
ATP	Adenosine-5'-triphosphate	C10 H16 N5 O13 P3	4

Primary citation

Hidden dynamics of ubiquitin-mediated proteasome autoregulation during protein degradation. Wu, Z., Chen, E., Zou, S. et al. To be published.

Other PDB entries of the same protein (UniProt P35998 (AlphaFold model), which also has an AlphaFold model), best resolution first:

9K53 2.5 Å, Structure of substrate-engaged human 26S proteasome RP-CP subcomplex in state ED2.1
8USD 2.7 Å, Rpn1/Nub1UBL-focused alignment of the non-substrate-engaged human 26S proteasome
8USB 2.73 Å, Non-substrate-engaged human 26S proteasome with Nub1/FAT10 bound to Rpn1
9MBP 2.75 Å, Substrate-engaged human 26S proteasome bound to midnolin with RPT1 at top of spiral…
9PDL 2.76 Å, Nub1/Fat10-processing human 26S proteasome with Rpt5 at top of spiral staircase (AAA+…
9NKG 2.8 Å, Structure of substrate engaged MIDN-bound human 26S proteasome, EB-MIDN (Composite map)
9E8I 2.87 Å, Human proteasome in resting state conformation bound to TXNL1 in Forward conformation
9BV3 2.9 Å, M1B Midnolin-Proteasome
9E8H 2.9 Å, Human proteasome in resting state conformation bound to TXNL1 in backward conformation
9K4J 2.9 Å, Structure of substrate-engaged human 26S proteasome RP-CP subcomplex in state EA1.0
9NKF 2.9 Å, Structure of human substrate-free 26S proteasome in the presence of ATPgS and…
9U3L 2.91 Å, Substrate-engaged human 26S proteasome bound to midnolin with RPT2 at top of spiral…

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