9SMS: BRCA1-A complex: Ubiquitin

BRCA1-A complex: Ubiquitin bound to BRE at the wrist site (focused 3D class). Determined by electron microscopy at 3.3 Å resolution. Released 17 Jun 2026.

Method: Electron microscopy
Resolution: 3.3 Å
Organism: Homo sapiens
Chains: 5
Atoms: 6,410
Mol. weight: 156.86 kDa
Released: 17 Jun 2026

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

Secondary structure: helices and β-sheets

9SMS contains 31 α-helices and 40 β-strands across 5 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: 1 helix, 2 β-strands

Element	Residues	Length	Sheet
α-helix	278-287	10
β-strand	299-300	2	1
β-strand	306	1	1

Chain C: 14 helices, 15 β-strands

Element	Residues	Length	Sheet
α-helix	3-8	6
α-helix	15-24	10
β-strand	36-42	7	2
β-strand	53-62	10	2
β-strand	65-72	8	2
α-helix	81-82	2
β-strand	83-85	3	2
α-helix	100-103	4
α-helix	112-133	22
α-helix	136-147	12
α-helix	149-152	4
β-strand	155-158	4	3
α-helix	159-161	3
β-strand	171-176	6	3
α-helix	184-186	3
β-strand	194-195	2	4
β-strand	201-207	7	3
β-strand	215-221	7	3
α-helix	223-229	7
β-strand	237	1	5
α-helix	238-240	3
α-helix	249-281	33
β-strand	286-289	4	6
β-strand	296-303	8	6
β-strand	306-313	8	6
α-helix	322-323	2
β-strand	324-328	5	6
β-strand	341-343	3	6
α-helix	355-380	26

Chain D: 9 helices, 12 β-strands

Element	Residues	Length	Sheet
β-strand	82-84	3	1
β-strand	93	1	7
β-strand	94-99	6	8
α-helix	103-106	4
β-strand	110-111	2	9
β-strand	117-118	2	9
α-helix	120-138	19
β-strand	143-148	6	8
β-strand	154-160	7	8
α-helix	163-172	10
α-helix	184-193	10
α-helix	195-197	3
β-strand	210	1	7
β-strand	211-217	7	8
α-helix	230-237	8
β-strand	241-249	9	8
α-helix	255-271	17
β-strand	279-283	5	8
β-strand	287	1	9
α-helix	288-298	11
α-helix	308-310	3

Chain E: 4 helices, 4 β-strands

Element	Residues	Length	Sheet
β-strand	273-276	4	1
α-helix	283-284	2
α-helix	289-312	24
β-strand	316-317	2	4
α-helix	323	1
β-strand	324	1	3
β-strand	326	1	5
α-helix	327-328	2

Chain S: 3 helices, 7 β-strands

Element	Residues	Length	Sheet
β-strand	2-6	5	10
β-strand	12-16	5	10
β-strand	22	1	11
α-helix	23-33	11
β-strand	41-45	5	10
β-strand	48-49	2	10
α-helix	50-51	2
β-strand	55	1	11
α-helix	57-59	3
β-strand	66-71	6	10

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
BRCA1-A complex subunit Abraxas 1	A	protein	409	Homo sapiens	Q6UWZ7 (AlphaFold model)
BRISC and BRCA1-A complex member 2	C	protein	383	Homo sapiens	Q9NXR7 (AlphaFold model)
BRISC and BRCA1-A complex member 1	D	protein	349	Homo sapiens	Q9NWV8 (AlphaFold model)
BRCA1-A complex subunit RAP80	E	protein	171	Homo sapiens	Q96RL1 (AlphaFold model)
Ubiquitin	S	protein	76	Homo sapiens	P0CG48

Sequence of entity 1 (A), FASTA

>9SMS_1 BRCA1-A complex subunit Abraxas 1 (chains A)
MEGESTSAVLSGFVLGALAFQHLNTDSDTEGFLLGEVKGEAKNSITDSQMDDVEVVYTID
IQKYIPCYQLFSFYNSSGEVNEQALKKILSNVKKNVVGWYKFRRHSDQIMTFRERLLHKN
LQEHFSNQDLVFLLLTPSIITESCSTHRLEHSLYKPQKGLFHRVPLVVANLGMSEQLGYK
TVSGSCMSTGFSRAVQTHSSKFFEEDGSLKEVHKINEMYASLQEELKSICKKVEDSEQAV
DKLVKDVNRLKREIEKRRGAQIQAAREKNIQKDPQENIFLCQALRTFFPNSEFLHSCVMS
LKNRHVSKSSCNYNHHLDVVDNLTLMVEHTDIPEASPASTPQIIKHKALDLDDRWQFKRS
RLLDTQDKRSKADTGSSNQDKASKMSSPETDEEIEKMKGFGEYSRSPTF

Sequence of entity 2 (C), FASTA

>9SMS_2 BRISC and BRCA1-A complex member 2 (chains C)
MSPEVALNRISPMLSPFISSVVRNGKVGLDATNCLRITDLKSGCTSLTPGPNCDRFKLHI
PYAGETLKWDIIFNAQYPELPPDFIFGEDAEFLPDPSALQNLASWNPSNPECLLLVVKEL
VQQYHQFQCSRLRESSRLMFEYQTLLEEPQYGENMEIYAGKKNNWTGEFSARFLLKLPVD
FSNIPTYLLKDVNEDPGEDVALLSVSFEDTEATQVYPKLYLSPRIEHALGGSSALHIPAF
PGGGCLIDYVPQVCHLLTNKVQYVIQGYHKRREYIAAFLSHFGTGVVEYDAEGFTKLTLL
LMWKDFCFLVHIDLPLFFPRDQPTLTFQSVYHFTNSGQLYSQAQKNYPYSPRWDGNEMAK
RAKAYFKTFVPQFQEAAFANGKL

Sequence of entity 3 (D), FASTA

>9SMS_3 BRISC and BRCA1-A complex member 1 (chains D)
MAHHHHHHSAALEVLFQGPGMEVAEPSSPTEEEEEEEEHSAEPRPRTRSNPEGAEDRAVG
AQASVGSRSEGEGEAASADDGSLNTSGAGPKSWQVPPPAPEVQIRTPRVNCPEKVIICLD
LSEEMSLPKLESFNGSKTNALNVSQKMIEMFVRTKHKIDKSHEFALVVVNDDTAWLSGLT
SDPRELCSCLYDLETASCSTFNLEGLFSLIQQKTELPVTENVQTIPPPYVVRTILVYSRP
PCQPQFSLTEPMKKMFQCPYFFFDVVYIHNGTEEKEEEMSWKDMFAFMGSLDTKGTSYKY
EVALAGPALELHNCMAKLLAHPLQRPCQSHASYSLLEEEDEAIEVEATV

Sequence of entity 4 (E), FASTA

>9SMS_4 BRCA1-A complex subunit RAP80 (chains E)
MASWSHPQFEKGALEVLFQGPGKGLQDTGGTVNYFWGIPFCPDGVDPNQYTKVILCQLEV
YQKSLKMAQRQLLNKKGFGEPVLPRPPSLIQNECGQGEQASEKNECISEDMGDEDKEERQ
ESRASDWHSKTKDFQESSIKSLKEKLLLEEEPTTSHGQSSQGIVEETSEEG

Sequence of entity 5 (S), FASTA

>9SMS_5 Ubiquitin (chains S)
MQIFVKTLTGKTITLEVEPSDTIENVKAKIQDKEGIPPDQQRLIFAGKQLEDGRTLSDYN
IQKESTLHLVLRLRGG

Primary citation

A ubiquitin chain-feeding mechanism for BRCA1-A. Murachelli, A.G., El Oualid, F., Sixma, T.K. Nat Commun (2026) 17. DOI 10.1038/s41467-026-75797-w · PubMed

Other PDB entries of the same protein (UniProt Q6UWZ7 (AlphaFold model), which also has an AlphaFold model), best resolution first:

4Y2G 2.5 Å, Structure of BRCA1 BRCT domains in complex with Abraxas single phosphorylated peptide
9SQY 2.92 Å, Cryo-EM structure of the ARISC(E33A)-RAP80:K63-Ub7 complex (Composite map)
9SMP 3.0 Å, BRCA1-A complex bound to K63-polyUbATA - open form double State P
9SMN 3.2 Å, BRCA1-A complex bound to K63-polyUbATA - open form StateC StateP
9SNA 3.2 Å, BRCA1-A complex bound to K63-diUbATA - open form StateC StateP
9SQW 3.2 Å, Cryo-EM structure of the ARISCdC(E33A):K63-Ub7 complex (Composite map)
9SQV 3.21 Å, Cryo-EM structure of the ARISCdC(E33A):K63-Ub4 complex (Composite map)
9SMR 3.25 Å, Structure of apo BRCA1-A complex in presence of K63-oligoUbATA
9SO9 3.4 Å, BRCA1-A complex bound to K63-oligoUbATA - closed form StateC*
4JLU 3.5 Å, Crystal structure of BRCA1 BRCT with doubly phosphorylated Abraxas
4Y18 3.5 Å, Structure of BRCA1 BRCT domains in complex with Abraxas double phosphorylated peptide
4U4A 3.51 Å, Complex Structure of BRCA1 BRCT with singly phospho Abraxas

Browse structure collections

About this viewer

MolViewer shows 9SMS directly in your browser with nothing to install. Switch between cartoon, ball-and-stick, spacefill and surface views, color by chain, secondary structure or B-factor, measure distances, angles and dihedrals, and share or embed the view.