9U7R: 26S proteasome non-ATPase regulatory subunit 14

Substrate-free human 26S proteasome purified by midnolin, 20S proteasome, RPTs and RPN11 part. Determined by electron microscopy at 3.17 Å resolution. Released 1 Apr 2026.

Method: Electron microscopy
Resolution: 3.17 Å
Organism: Homo sapiens
Chains: 35
Atoms: 66,567
Mol. weight: 1085.31 kDa
Ligands: MG, LDZ, ADP, ATP
Released: 1 Apr 2026

Explore 9U7R in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9U7R contains 353 α-helices and 468 β-strands across 35 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: 21 helices, 17 β-strands

Element	Residues	Length	Sheet
α-helix	82-85	4
α-helix	86-90	5
β-strand	97-100	4	7
β-strand	104	1	8
β-strand	111-112	2	8
β-strand	122-123	2	8
β-strand	125	1	7
β-strand	139-142	4	7
β-strand	149-153	5	7
α-helix	159-162	4
β-strand	165	1	9
α-helix	169-170	2
α-helix	174-176	3
α-helix	181-191	11
α-helix	193-196	4
α-helix	199-204	6
β-strand	212-215	4	9
α-helix	222-232	11
β-strand	236-241	6	9
α-helix	242-244	3
α-helix	252-266	15
β-strand	270-275	6	9
α-helix	277-279	3
β-strand	282	1	10
α-helix	283-284	2
β-strand	287	1	11
β-strand	290	1	11
α-helix	294-306	13
β-strand	315-321	7	9
β-strand	327	1	10
β-strand	339-342	4	9
α-helix	344-346	3
α-helix	348-357	10
α-helix	370-375	6
α-helix	382-398	17
α-helix	406-413	8
α-helix	414-419	6
α-helix	426-429	4

Chain B: 18 helices, 14 β-strands

Element	Residues	Length	Sheet
α-helix	92-102	11
β-strand	108-114	7	14
β-strand	121-124	4	14
β-strand	130-133	4	14
β-strand	135	1	14
β-strand	149-152	4	14
β-strand	159-162	4	14
α-helix	169-174	6
β-strand	175	1	15
α-helix	184-186	3
α-helix	192-201	10
α-helix	203-206	4
α-helix	209-214	6
α-helix	217-219	3
β-strand	221-225	5	15
α-helix	232-242	11
β-strand	246-251	6	15
α-helix	253-255	3
α-helix	262-277	16
β-strand	280-285	6	15
α-helix	289-292	4
α-helix	302-316	15
β-strand	325-331	7	15
α-helix	334-336	3
β-strand	349-352	4	15
α-helix	355-357	3
α-helix	358-368	11
β-strand	374	1	16
α-helix	380-383	4
α-helix	392-408	17
β-strand	414	1	16
α-helix	416-426	11

Chain c: 13 helices, 10 β-strands

Element	Residues	Length	Sheet
β-strand	31-33	3	1
α-helix	35-47	13
β-strand	54-58	5	2
β-strand	61	1	3
β-strand	67	1	3
β-strand	71-74	4	2
α-helix	75-77	3
α-helix	89-98	10
β-strand	108-114	7	2
α-helix	124-136	13
β-strand	141-145	5	2
β-strand	159-162	4	2
α-helix	163-164	2
α-helix	165-170	6
α-helix	172-173	2
α-helix	186-188	3
α-helix	189-193	5
β-strand	200-203	4	2
β-strand	205-207	3	1
α-helix	211-219	9
α-helix	234-261	28
α-helix	267-273	7
α-helix	282-308	27

Chain C: 20 helices, 12 β-strands

Element	Residues	Length	Sheet
α-helix	39-65	27
β-strand	71-79	9	14
β-strand	84-89	6	14
β-strand	94-98	5	14
β-strand	113-117	5	14
β-strand	122-126	5	14
α-helix	133-141	9
α-helix	143-145	3
α-helix	148-150	3
α-helix	156-161	6
α-helix	162-166	5
α-helix	167-170	4
α-helix	172-178	7
α-helix	180-183	4
β-strand	185-189	5	21
α-helix	197-206	10
β-strand	210-213	4	21
α-helix	221-224	4
α-helix	234-240	7
β-strand	244-249	6	21
α-helix	268-279	12
β-strand	289-295	7	21
α-helix	298-300	3
β-strand	313-316	4	21
α-helix	318-320	3
α-helix	322-332	11
β-strand	338	1	22
α-helix	339	1
α-helix	344-349	6
α-helix	356-372	17
β-strand	378	1	22
α-helix	380-395	16

Chain D: 20 helices, 13 β-strands

Element	Residues	Length	Sheet
α-helix	54-62	9
α-helix	65-77	13
α-helix	80-82	3
β-strand	87-94	8	14
β-strand	101-105	5	14
β-strand	109-113	5	14
β-strand	115	1	14
α-helix	121-123	3
β-strand	129-133	5	14
β-strand	139-142	4	14
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	27
α-helix	212-222	11
β-strand	226-231	6	27
α-helix	232-234	3
α-helix	242-257	16
β-strand	260-265	6	27
α-helix	267-270	4
β-strand	272	1	28
α-helix	281-296	16
β-strand	305-311	7	27
α-helix	314-316	3
β-strand	317	1	28
α-helix	319-322	4
β-strand	329-332	4	27
α-helix	338-349	12
α-helix	361-364	4
α-helix	372-388	17
α-helix	396-407	12
α-helix	415-417	3

Chain E: 16 helices, 12 β-strands

Element	Residues	Length	Sheet
α-helix	44-49	6
β-strand	55-63	9	14
β-strand	69-73	5	14
β-strand	78-83	6	14
β-strand	97-100	4	14
β-strand	106-111	6	14
α-helix	112-114	3
α-helix	117-123	7
α-helix	140-149	10
α-helix	151-154	4
α-helix	157-162	6
β-strand	169-173	5	31
α-helix	181-190	10
β-strand	194-198	5	31
α-helix	210-224	15
β-strand	228-233	6	31
α-helix	236-239	4
α-helix	250-264	15
β-strand	273-279	7	31
α-helix	282-284	3
β-strand	297-300	4	31
α-helix	306-315	10
β-strand	322	1	32
α-helix	330-334	5
α-helix	342-355	14
β-strand	362	1	32
α-helix	364-377	14
α-helix	378-380	3

Chain F: 19 helices, 16 β-strands

Element	Residues	Length	Sheet
α-helix	75-84	10
β-strand	88-95	8	14
β-strand	122-126	5	14
β-strand	130-134	5	14
β-strand	138	1	14
α-helix	142-144	3
β-strand	150-154	5	14
β-strand	160-163	4	14
α-helix	170-175	6
β-strand	176	1	38
α-helix	185-187	3
α-helix	193-207	15
α-helix	209-215	7
α-helix	217-220	4
β-strand	223-226	4	38
α-helix	233-243	11
β-strand	247-250	4	38
α-helix	254-256	3
α-helix	263-277	15
β-strand	281-285	5	38
α-helix	288-290	3
β-strand	293	1	39
α-helix	294-295	2
α-helix	305-317	13
β-strand	326-331	6	38
β-strand	338	1	39
β-strand	350-353	4	38
α-helix	355-357	3
α-helix	359-368	10
β-strand	375	1	40
α-helix	381-387	7
α-helix	393-409	17
β-strand	415	1	40
α-helix	417-428	12
α-helix	430-432	3

Chain g: 9 helices, 14 β-strands

Element	Residues	Length	Sheet
α-helix	23-28	6
α-helix	29-35	7
β-strand	38-43	6	99
β-strand	47-53	7	99
β-strand	61	1	100
β-strand	69-71	3	101
β-strand	76-79	4	101
β-strand	82	1	102
α-helix	84-105	22
α-helix	108-110	3
α-helix	111-125	15
β-strand	128	1	103
β-strand	136	1	102
β-strand	139-144	6	101
β-strand	148-154	7	101
β-strand	160-163	4	101
β-strand	165-169	5	99
α-helix	172-184	13
α-helix	191-206	16
β-strand	215-221	7	99
β-strand	228-229	2	99
α-helix	230-231	2
α-helix	232-242	11

27 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 non-ATPase regulatory subunit 14	c	protein	309	Homo sapiens	O00487 (AlphaFold model)
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
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	245	Homo sapiens	P60900
Proteasome subunit alpha type-2	H, h	protein	233	Homo sapiens	P25787
Proteasome subunit alpha type-4	I, i	protein	260	Homo sapiens	P25789
Proteasome subunit alpha type-7	J, j	protein	247	Homo sapiens	O14818
Proteasome subunit alpha type-5	K, k	protein	240	Homo sapiens	P28066

9 more molecules are not listed.

Sequence of entity 1 (c), FASTA

>9U7R_1 26S proteasome non-ATPase regulatory subunit 14 (chains c)
DRLLRLGGGMPGLGQGPPTDAPAVDTAEQVYISSLALLKMLKHGRAGVPMEVMGLMLGEF
VDDYTVRVIDVFAMPQSGTGVSVEAVDPVFQAKMLDMLKQTGRPEMVVGWYHSHPGFGCW
LSGVDINTQQSFEALSERAVAVVVDPIQSVKGKVVIDAFRLINANMMVLGHEPRQTTSNL
GHLNKPSIQALIHGLNRHYYSITINYRKNELEQKMLLNLHKKSWMEGLTLQDYSEHCKHN
ESVVKEMLELAKNYNKAVEEEDKMTPEQLAIKNVGKQDPKRHLEEHVDVLMTSNIVQCLA
AMLDTVVFK

Sequence of entity 2 (A), FASTA

>9U7R_2 26S proteasome regulatory subunit 7 (chains A)
MPDYLGADQRKTKEDEKDDKPIRALDEGDIALLKTYGQSTYSRQIKQVEDDIQQLLKKIN
ELTGIKESDTGLAPPALWDLAADKQTLQSEQPLQVARCTKIINADSEDPKYIINVKQFAK
FVVDLSDQVAPTDIEEGMRVGVDRNKYQIHIPLPPKIDPTVTMMQVEEKPDVTYSDVGGC
KEQIEKLREVVETPLLHPERFVNLGIEPPKGVLLFGPPGTGKTLCARAVANRTDACFIRV
IGSELVQKYVGEGARMVRELFEMARTKKACLIFFDEIDAIGGARFDDGAGGDNEVQRTML
ELINQLDGFDPRGNIKVLMATNRPDTLDPALMRPGRLDRKIEFSLPDLEGRTHIFKIHAR
SMSVERDIRFELLARLCPNSTGAEIRSVCTEAGMFAIRARRKIATEKDFLEAVNKVIKSY
AKFSATPRYMTYN

Sequence of entity 3 (B), FASTA

>9U7R_3 26S proteasome regulatory subunit 4 (chains B)
MGQSQSGGHGPGGGKKDDKDKKKKYEPPVPTRVGKKKKKTKGPDAASKLPLVTPHTQCRL
KLLKLERIKDYLLMEEEFIRNQEQMKPLEEKQEEERSKVDDLRGTPMSVGTLEEIIDDNH
AIVSTSVGSEHYVSILSFVDKDLLEPGCSVLLNHKVHAVIGVLMDDTDPLVTVMKVEKAP
QETYADIGGLDNQIQEIKESVELPLTHPEYYEEMGIKPPKGVILYGPPGTGKTLLAKAVA
NQTSATFLRVVGSELIQKYLGDGPKLVRELFRVAEEHAPSIVFIDEIDAIGTKRYDSNSG
GEREIQRTMLELLNQLDGFDSRGDVKVIMATNRIETLDPALIRPGRIDRKIEFPLPDEKT
KKRIFQIHTSRMTLADDVTLDDLIMAKDDLSGADIKAICTEAGLMALRERRMKVTNEDFK
KSKENVLYKKQEGTPEGLYL

Sequence of entity 4 (C), FASTA

>9U7R_4 26S proteasome regulatory subunit 8 (chains C)
MELEEGKAGSGLRQYYLSKIEELQLIVNDKSQNLRRLQAQRNELNAKVRLLREELQLLQE
QGSYVGEVVRAMDKKKVLVKVHPEGKFVVDVDKNIDINDVTPNCRVALRNDSYTLHKILP
NKVDPLVSLMMVEKVPDSTYEMIGGLDKQIKEIKEVIELPVKHPELFEALGIAQPKGVLL
YGPPGTGKTLLARAVAHHTDCTFIRVSGSELVQKFIGEGARMVRELFVMAREHAPSIIFM
DEIDSIGSSRLEGGSGGDSEVQRTMLELLNQLDGFEATKNIKVIMATNRIDILDSALLRP
GRIDRKIEFPPPNEEARLDILKIHSRKMNLTRGINLRKIAELMPGASGAEVKGVCTEAGM
YALRERRVHVTQEDFEMAVAKVMQKDSEKNMSIKKLWK

Sequence of entity 5 (D), FASTA

>9U7R_5 26S proteasome regulatory subunit 6B (chains D)
MEEIGILVEKAQDEIPALSVSRPQTGLSFLGPEPEDLEDLYSRYKKLQQELEFLEVQEEY
IKDEQKNLKKEFLHAQEEVKRIQSIPLVIGQFLEAVDQNTAIVGSTTGSNYYVRILSTID
RELLKPNASVALHKHSNALVDVLPPEADSSIMMLTSDQKPDVMYADIGGMDIQKQEVREA
VELPLTHFELYKQIGIDPPRGVLMYGPPGCGKTMLAKAVAHHTTAAFIRVVGSEFVQKYL
GEGPRMVRDVFRLAKENAPAIIFIDEIDAIATKRFDAQTGADREVQRILLELLNQMDGFD
QNVNVKVIMATNRADTLDPALLRPGRLDRKIEFPLPDRRQKRLIFSTITSKMNLSEEVDL
EDYVARPDKISGADINSICQESGMLAVRENRYIVLAKDFEKAYKTVIKKDEQEHEFYK

Sequence of entity 6 (E), FASTA

>9U7R_6 Proteasome 26S subunit, ATPase 6 (chains E)
MAIPGIPYERRLLIMADPRDKALQDYRKKLLEHKEIDGRLKELREQLKELTKQYEKSEND
LKALQSVGQIVGEVLKQLTEEKFIVKATNGPRYVVGCRRQLDKSKLKPGTRVALDMTTLT
IMRYLPREVDPLVYNMSHEDPGNVSYSEIGGLSEQIRELREVIELPLTNPELFQRVGIIP
PKGCLLYGPPGTGKTLLARAVASQLDCNFLKVVSSSIVDKYIGESARLIREMFNYARDHQ
PCIIFMDEIDAIGGRRFSEGTSADREIQRTLMELLNQMDGFDTLHRVKMIMATNRPDTLD
PALLRPGRLDRKIHIDLPNEQARLDILKIHAGPITKHGEIDYEAIVKLSDGFNGADLRNV
CTEAGMFAIRADHDFVVQEDFMKAVRKVADSKKLESKLDYKPV

Sequence of entity 7 (F), FASTA

>9U7R_7 26S proteasome regulatory subunit 6A (chains F)
MNLLPNIESPVTRQEKMATVWDEAEQDGIGEEVLKMSTEEIIQRTRLLDSEIKIMKSEVL
RVTHELQAMKDKIKENSEKIKVNKTLPYLVSNVIELLDVDPNDQEEDGANIDLDSQRKGK
CAVIKTSTRQTYFLPVIGLVDAEKLKPGDLVGVNKDSYLILETLPTEYDSRVKAMEVDER
PTEQYSDIGGLDKQIQELVEAIVLPMNHKEKFENLGIQPPKGVLMYGPPGTGKTLLARAC
AAQTKATFLKLAGPQLVQMFIGDGAKLVRDAFALAKEKAPSIIFIDELDAIGTKRFDSEK
AGDREVQRTMLELLNQLDGFQPNTQVKVIAATNRVDILDPALLRSGRLDRKIEFPMPNEE
ARARIMQIHSRKMNVSPDVNYEELARCTDDFNGAQCKAVCVEAGMIALRRGATELTHEDY
MEGILEVQAKKKANLQYYA

Sequence of entity 8 (G, g), FASTA

>9U7R_8 Proteasome subunit alpha type-6 (chains G, g)
SRGSSAGFDRHITIFSPEGRLYQVEYAFKAINQGGLTSVAVRGKDCAVIVTQKKVPDKLL
DSSTVTHLFKITENIGCVMTGMTADSRSQVQRARYEAANWKYKYGYEIPVDMLCKRIADI
SQVYTQNAEMRPLGCCMILIGIDEEQGPQVYKCDPAGYYCGFKATAAGVKQTESTSFLEK
KVKKKFDWTFEQTVETAITCLSTVLSIDFKPSEIEVGVVTVENPKFRILTEAEIDAHLVA
LAERD

Sequence of entity 9 (H, h), FASTA

>9U7R_9 Proteasome subunit alpha type-2 (chains H, h)
AERGYSFSLTTFSPSGKLVQIEYALAAVAGGAPSVGIKAANGVVLATEKKQKSILYDERS
VHKVEPITKHIGLVYSGMGPDYRVLVHRARKLAQQYYLVYQEPIPTAQLVQRVASVMQEY
TQSGGVRPFGVSLLICGWNEGRPYLFQSDPSGAYFAWKATAMGKNYVNGKTFLEKRYNED
LELEDAIHTAILTLKESFEGQMTEDNIEVGICNEAGFRRLTPTEVKDYLAAIA

Sequence of entity 10 (I, i), FASTA

>9U7R_10 Proteasome subunit alpha type-4 (chains I, i)
SRRYDSRTTIFSPEGRLYQVEYAMEAIGHAGTCLGILANDGVLLAAERRNIHKLLDEVFF
SEKIYKLNEDMACSVAGITSDANVLTNELRLIAQRYLLQYQEPIPCEQLVTALCDIKQAY
TQFGGKRPFGVSLLYIGWDKHYGFQLYQSDPSGNYGGWKATCIGNNSAAAVSMLKQDYKE
GEMTLKSALALAIKVLNKTMDVSKLSAEKVEIATLTRENGKTVIRVLKQKEVEQLIKKHE
EEEAKAEREKKEKEQKEKDK

Sequence of entity 11 (J, j), FASTA

>9U7R_11 Proteasome subunit alpha type-7 (chains J, j)
SYDRAITVFSPDGHLFQVEYAQEAVKKGSTAVGVRGRDIVVLGVEKKSVAKLQDERTVRK
ICALDDNVCMAFAGLTADARIVINRARVECQSHRLTVEDPVTVEYITRYIASLKQRYTQS
NGRRPFGISALIVGFDFDGTPRLYQTDPSGTYHAWKANAIGRGAKSVREFLEKNYTDEAI
ETDDLTIKLVIKALLEVVQSGGKNIELAVMRRDQSLKILNPEEIEKYVAEIEKEKEENEK
KKQKKAS

Sequence of entity 12 (K, k), FASTA

>9U7R_12 Proteasome subunit alpha type-5 (chains K, k)
FLTRSEYDRGVNTFSPEGRLFQVEYAIEAIKLGSTAIGIQTSEGVCLAVEKRITSPLMEP
SSIEKIVEIDAHIGCAMSGLIADAKTLIDKARVETQNHWFTYNETMTVESVTQAVSNLAL
QFGEEDADPGAMSRPFGVALLFGGVDEKGPQLFHMDPSGTFVQCDARAIGSASEGAQSSL
QEVYHKSMTLKEAIKSSLIILKQVMEEKLNATNIELATVQPGQNFHMFTKEELEEVIKDI

Ligands and cofactors

ID	Name	Formula	Copies
MG	Magnesium ion	Mg	4
LDZ	N-[(benzyloxy)carbonyl]-L-leucyl-N-[(2S)-4-methyl-1-oxopentan-2-yl]-L-leucinami…	C26 H41 N3 O5	6
ADP	Adenosine-5'-diphosphate	C10 H15 N5 O10 P2	2
ATP	Adenosine-5'-triphosphate	C10 H16 N5 O13 P3	4
ZN	Zinc ion	Zn	1

Primary citation

Structural dynamics of the midnolin-proteasome during ubiquitin-independent substrate turnover. Zhu, C., Qin, L., Dai, Z. et al. Nat Commun (2026) 17. DOI 10.1038/s41467-026-71002-0 · PubMed

Other PDB entries of the same protein (UniProt O00487 (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
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…
9NKI 2.94 Å, Structure of substrate engaged MIDN-bound human 26S proteasome, EB MIDN_UBL state…

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