9MC7: Human UBA1-UBE2O-Ub -Recruitment state 4

Cryo-EM structure of Human UBA1-UBE2O-Ub -Recruitment state 4. Determined by electron microscopy at 3.34 Å resolution. Released 25 Mar 2026.

Method: Electron microscopy
Resolution: 3.34 Å
Organism: Homo sapiens
Chains: 3
Atoms: 9,434
Mol. weight: 167.31 kDa
Ligands: AMP
Released: 25 Mar 2026

Explore 9MC7 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9MC7 contains 66 α-helices and 68 β-strands across 3 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: 49 helices, 53 β-strands

Element	Residues	Length	Sheet
β-strand	74-78	5	1
α-helix	84-94	11
β-strand	98-102	5	1
β-strand	106	1	2
α-helix	107	1
α-helix	109-111	3
α-helix	120-122	3
β-strand	126	1	2
α-helix	127-135	9
β-strand	144-147	4	1
α-helix	155-158	4
β-strand	161-165	5	1
α-helix	169-182	14
β-strand	185-192	8	1
β-strand	195-201	7	1
β-strand	206-208	3	3
α-helix	214-217	4
β-strand	218-220	3	4
β-strand	221-225	5	5
β-strand	231-234	4	5
β-strand	247-251	5	4
β-strand	254	1	6
β-strand	265-266	2	4
β-strand	268-269	2	5
β-strand	274-276	3	5
α-helix	284-286	3
β-strand	288	1	6
β-strand	291-294	4	4
β-strand	299-301	3	3
α-helix	306-310	5
β-strand	315-316	2	1
α-helix	320-322	3
α-helix	325-343	19
α-helix	346-348	3
α-helix	352-367	16
α-helix	380-389	10
α-helix	395-414	20
α-helix	418-420	3
β-strand	423-427	5	1
α-helix	429-431	3
α-helix	442-444	3
α-helix	452-457	6
α-helix	460-468	9
β-strand	470-474	5	7
α-helix	478-490	13
β-strand	494	1	8
β-strand	499-503	5	7
α-helix	506	1
β-strand	507	1	9
α-helix	508	1
α-helix	510-514	5
α-helix	521-523	3
β-strand	527	1	9
α-helix	528-539	12
β-strand	543	1	8
β-strand	545-548	4	7
α-helix	562-567	6
β-strand	570-573	4	7
α-helix	578-590	13
β-strand	595-601	7	7
β-strand	602	1	10
β-strand	604-610	7	7
β-strand	615	1	11
α-helix	631-634	4
α-helix	641-656	16
α-helix	713-715	3
α-helix	716-720	5
α-helix	721-728	8
β-strand	734	1	12
β-strand	740	1	12
α-helix	759-768	10
α-helix	822-829	8
α-helix	858-871	14
α-helix	880-887	8
α-helix	890-892	3
β-strand	893	1	10
α-helix	895-913	19
α-helix	919-921	3
β-strand	924-928	5	7
β-strand	933-937	5	7
β-strand	938	1	13
α-helix	939-940	2
β-strand	941	1	11
α-helix	942-943	2
β-strand	944-947	4	14
β-strand	950-953	4	14
β-strand	958-961	4	15
β-strand	963	1	16
β-strand	969	1	16
α-helix	972-978	7
α-helix	979-983	5
α-helix	985	1
β-strand	986-991	6	17
β-strand	992	1	18
β-strand	995	1	18
α-helix	1004-1010	7
α-helix	1015-1023	9
β-strand	1033-1036	4	15
β-strand	1037-1041	5	17
β-strand	1047-1049	3	17
α-helix	1051-1052	2
β-strand	1053-1056	4	15

Chain B: 14 helices, 8 β-strands

Element	Residues	Length	Sheet
α-helix	929-931	3
α-helix	951-968	18
α-helix	969-970	2
β-strand	973-977	5	19
β-strand	984-990	7	19
β-strand	991	1	20
β-strand	998	1	20
β-strand	1001-1007	7	19
α-helix	1012-1014	3
α-helix	1016-1017	2
β-strand	1018-1021	4	19
β-strand	1033-1034	2	21
β-strand	1038-1039	2	21
α-helix	1042-1044	3
α-helix	1051-1053	3
α-helix	1062-1067	6
α-helix	1068-1072	5
α-helix	1077-1080	4
α-helix	1084-1087	4
α-helix	1091-1117	27
α-helix	1124-1150	27
α-helix	1263-1283	21

Chain C: 3 helices, 7 β-strands

Element	Residues	Length	Sheet
β-strand	2-7	6	13
α-helix	11	1
β-strand	12-16	5	13
β-strand	22	1	22
α-helix	23-34	12
β-strand	42-45	4	13
β-strand	48-49	2	13
β-strand	55	1	22
α-helix	56-59	4
β-strand	66-70	5	13

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Ubiquitin-like modifier-activating enzyme 1	A	protein	1058	Homo sapiens	P22314 (AlphaFold model)
(E3-independent) E2 ubiquitin-conjugating enzyme	B	protein	365	Homo sapiens	Q9C0C9 (AlphaFold model)
Ubiquitin	C	protein	76	Homo sapiens	P0CG47 (AlphaFold model)

Sequence of entity 1 (A), FASTA

>9MC7_1 Ubiquitin-like modifier-activating enzyme 1 (chains A)
MSSSPLSKKRRVSGPDPKPGSNCSPAQSVLSEVPSVPTNGMAKNGSEADIDEGLYSRQLY
VLGHEAMKRLQTSSVLVSGLRGLGVEIAKNIILGGVKAVTLHDQGTAQWADLSSQFYLRE
EDIGKNRAEVSQPRLAELNSYVPVTAYTGPLVEDFLSGFQVVVLTNTPLEDQLRVGEFCH
NRGIKLVVADTRGLFGQLFCDFGEEMILTDSNGEQPLSAMVSMVTKDNPGVVTCLDEARH
GFESGDFVSFSEVQGMVELNGNQPMEIKVLGPYTFSICDTSNFSDYIRGGIVSQVKVPKK
ISFKSLVASLAEPDFVVTDFAKFSRPAQLHIGFQALHQFCAQHGRPPRPRNEEDAAELVA
LAQAVNARALPAVQQNNLDEDLIRKLAYVAAGDLAPINAFIGGLAAQEVMKACSGKFMPI
MQWLYFDALECLPEDKEVLTEDKCLQRQNRYDGQVAVFGSDLQEKLGKQKYFLVGAGAIG
CELLKNFAMIGLGCGEGGEIIVTDMDTIEKSNLNRQFLFRPWDVTKLKSDTAAAAVRQMN
PHIRVTSHQNRVGPDTERIYDDDFFQNLDGVANALDNVDARMYMDRRCVYYRKPLLESGT
LGTKGNVQVVIPFLTESYSSSQDPPEKSIPICTLKNFPNAIEHTLQWARDEFEGLFKQPA
ENVNQYLTDPKFVERTLRLAGTQPLEVLEAVQRSLVLQRPQTWADCVTWACHHWHTQYSN
NIRQLLHNFPPDQLTSSGAPFWSGPKRCPHPLTFDVNNPLHLDYVMAAANLFAQTYGLTG
SQDRAAVATFLQSVQVPEFTPKSGVKIHVSDQELQSANASVDDSRLEELKATLPSPDKLP
GFKMYPIDFEKDDDSNFHMDFIVAASNLRAENYDIPSADRHKSKLIAGKIIPAIATTTAA
VVGLVCLELYKVVQGHRQLDSYKNGFLNLALPFFGFSEPLAAPRHQYYNQEWTLWDRFEV
QGLQPNGEEMTLKQFLDYFKTEHKLEITMLSQGVSMLYSFFMPAAKLKERLDQPMTEIVS
RVSKRKLGRHVRALVLELCCNDESGEDVEVPYVRYTIR

Sequence of entity 2 (B), FASTA

>9MC7_2 (E3-independent) E2 ubiquitin-conjugating enzyme (chains B)
VFSVLEFAPSNHSFKKIEFQPPEAKKFFSTVRKEMALLATSLPEGIMVKTFEDRMDLFSA
LIKGPTRTPYEDGLYLFDIQLPNIYPAVPPHFCYLSQCSGRLNPNLYDNGKVCVSLLGTW
IGKGTERWTSKSSLLQVLISIQGLILVNEPYYNEAGFDSDRGLQEGYENSRCYNEMALIR
VVQSMTQLVRRPPEVFEQEIRQHFSTGGWRLVNRIESWLETHALLEKAQALPNGVPKASS
SPEPPAVAELSDSGQQEPEDGGPAPGEASQGSDSEGGAQGLASASRDHTDQTSETAPDAS
VPPSVKPKKRRKSYRSFLPEKSGYPDIGFPLFPLSKGFIKSIRGVLTQFRAALLEAGMPE
CTEDK

Sequence of entity 3 (C), FASTA

>9MC7_3 Ubiquitin (chains C)
MQIFVKTLTGKTITLEVEPSDTIENVKAKIQDKEGIPPDQQRLIFAGKQLEDGRTLSDYN
IQKESTLHLVLRLRGG

Ligands and cofactors

ID	Name	Formula	Copies
AMP	Adenosine monophosphate	C10 H14 N5 O7 P	1

Primary citation

Cryo-EM structure of Human UBA1-UBE2O-Ub -Recruitment state 4. Chen, P.-T., Wu, K.-P. To be published.

Other PDB entries of the same protein (UniProt P22314 (AlphaFold model), which also has an AlphaFold model), best resolution first:

4P22 2.75 Å, Crystal Structure of N-terminal Fragments of E1
6DC6 3.14 Å, Crystal structure of human ubiquitin activating enzyme E1 (Uba1) in complex with ubiquitin
7PYV 3.27 Å, Crystal structure of human UBA6 in complex with the ubiquitin-like modifier FAT10
9MC5 3.29 Å, Cryo-EM structure of Human UBA1-UBE2O-Ub -Transthiolation state 3
9WD1 3.31 Å, Cryo-EM structure of Human UBA1-UBE2O-Ub -Recruitment state 3
9MC4 3.32 Å, Cryo-EM structure of Human UBA1-UBE2O-Ub -Transthiolation state 4
9MC6 3.32 Å, Cryo-EM structure of Human UBA1-UBE2O-Ub -Transthiolation state 2
9WD0 3.33 Å, Cryo-EM structure of Human UBA1-UBE2O-Ub -Recruitment state 2
9MC9 3.37 Å, Cryo-EM structure of Human UBA1-UBE2O-Ub -Transthiolation state 1
9MCB 3.42 Å, Cryo-EM structure of Human UBA1-UBE2O-Ub -Recruitment state 1

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