22FN: AsCas12a

Cryo-EM structure of AsCas12a in complex with crDNA and RNA target. Determined by electron microscopy at 3.17 Å resolution. Released 29 Apr 2026.

Method: Electron microscopy
Resolution: 3.17 Å
Organisms: synthetic construct, Acidaminococcus sp. BV3L6
Chains: 3
Atoms: 11,105
Mol. weight: 178.94 kDa
Released: 29 Apr 2026

Explore 22FN in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

22FN contains 61 α-helices and 47 β-strands across 1 chain. 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: 61 helices, 47 β-strands

Element	Residues	Length	Sheet
α-helix	4-6	3
β-strand	8	1	1
β-strand	13-23	11	2
α-helix	27-34	8
α-helix	36-67	32
α-helix	74-86	13
α-helix	89-111	23
α-helix	119-132	14
α-helix	136-139	4
α-helix	141-145	5
α-helix	153-161	9
α-helix	167-169	3
α-helix	170-179	10
α-helix	189-195	7
α-helix	197-214	18
α-helix	218-229	12
α-helix	237-240	4
α-helix	243-247	5
α-helix	252-263	12
β-strand	265-268	4	3
β-strand	272-274	3	3
α-helix	277-286	10
α-helix	290-296	7
α-helix	302-308	7
α-helix	326-342	17
α-helix	345-358	14
α-helix	361-363	3
β-strand	365-366	2	4
α-helix	368-370	3
α-helix	371-375	5
α-helix	404-415	12
β-strand	418-419	2	4
α-helix	420-427	8
α-helix	430-451	22
α-helix	453-455	3
α-helix	461-483	23
β-strand	484	1	4
α-helix	494-521	28
α-helix	524-526	3
β-strand	531-532	2	5
β-strand	545	1	6
α-helix	549-552	4
β-strand	554-559	6	2
β-strand	562-567	6	2
α-helix	568-571	4
β-strand	582	1	6
β-strand	589-597	9	6
α-helix	601-605	5
α-helix	606-610	5
α-helix	613-619	7
β-strand	626-628	3	7
β-strand	632	1	8
β-strand	636-638	3	7
α-helix	640-646	7
α-helix	657-663	7
α-helix	666-686	21
β-strand	687	1	8
α-helix	699-700	2
α-helix	701-703	3
α-helix	707-717	11
β-strand	719-727	9	6
α-helix	728-737	10
β-strand	741-746	6	2
α-helix	760-768	9
α-helix	771-775	5
β-strand	779-781	3	2
α-helix	782	1
β-strand	786-787	2	2
β-strand	788-789	2	5
β-strand	790	1	9
α-helix	791-793	3
β-strand	868	1	9
β-strand	869-877	9	2
α-helix	888-898	11
β-strand	904-908	5	10
β-strand	916-920	5	10
β-strand	926-931	6	10
α-helix	940-956	17
α-helix	965-986	22
β-strand	989-993	5	10
α-helix	1010-1023	14
β-strand	1026	1	1
β-strand	1043	1	1
β-strand	1058-1059	2	10
β-strand	1062-1065	4	10
β-strand	1083	1	11
α-helix	1091-1100	10
β-strand	1103-1107	5	12
β-strand	1112-1118	7	12
β-strand	1126	1	11
β-strand	1135-1140	6	12
α-helix	1141-1143	3
β-strand	1144-1147	4	13
β-strand	1153-1156	4	13
β-strand	1161	1	14
β-strand	1174	1	14
α-helix	1178-1188	11
α-helix	1193-1195	3
α-helix	1200-1204	5
α-helix	1209-1222	14
β-strand	1226-1227	2	15
β-strand	1236-1237	2	15
β-strand	1238	1	16
β-strand	1241	1	12
β-strand	1250	1	16
α-helix	1251-1253	3
α-helix	1263-1283	21
α-helix	1295-1306	12

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
RNA (5'-r(pgpapcpapgpcpcpcpapcpapupgpgpcpapupupcpcpapcp*u)-3')	B	RNA	45	synthetic construct
CRISPR-associated endonuclease Cas12a	A	protein	1307	Acidaminococcus sp. BV3L6	U2UMQ6 (AlphaFold model)
DNA (41-mer)	C	DNA	43	synthetic construct

Sequence of entity 1 (B), FASTA

>22FN_1 RNA (5'-R(P*GP*AP*CP*AP*GP*CP*CP*CP*AP*CP*AP*UP*GP*GP*CP*AP*UP*UP*CP*CP*AP*CP*U)-3') (chains B)
GACAGCCCACAUGGCAUUCCACUUAUCACUGGCAUCCUUCCACUC

Sequence of entity 2 (A), FASTA

>22FN_2 CRISPR-associated endonuclease Cas12a (chains A)
MTQFEGFTNLYQVSKTLRFELIPQGKTLKHIQEQGFIEEDKARNDHYKELKPIIDRIYKT
YADQCLQLVQLDWENLSAAIDSYRKEKTEETRNALIEEQATYRNAIHDYFIGRTDNLTDA
INKRHAEIYKGLFKAELFNGKVLKQLGTVTTTEHENALLRSFDKFTTYFSGFYENRKNVF
SAEDISTAIPHRIVQDNFPKFKENCHIFTRLITAVPSLREHFENVKKAIGIFVSTSIEEV
FSFPFYNQLLTQTQIDLYNQLLGGISREAGTEKIKGLNEVLNLAIQKNDETAHIIASLPH
RFIPLFKQILSDRNTLSFILEEFKSDEEVIQSFCKYKTLLRNENVLETAEALFNELNSID
LTHIFISHKKLETISSALCDHWDTLRNALYERRISELTGKITKSAKEKVQRSLKHEDINL
QEIISAAGKELSEAFKQKTSEILSHAHAALDQPLPTTLKKQEEKEILKSQLDSLLGLYHL
LDWFAVDESNEVDPEFSARLTGIKLEMEPSLSFYNKARNYATKKPYSVEKFKLNFQRPTL
ASGWDVNKEKNNGAILFVKNGLYYLGIMPKQKGRYKALSFEPTEKTSEGFDKMYYDYFPD
AAKMIPKCSTQLKAVTAHFQTHTTPILLSNNFIEPLEITKEIYDLNNPEKEPKKFQTAYA
KKTGDQKGYREALCKWIDFTRDFLSKYTKTTSIDLSSLRPSSQYKDLGEYYAELNPLLYH
ISFQRIAEKEIMDAVETGKLYLFQIYNKDFAKGHHGKPNLHTLYWTGLFSPENLAKTSIK
LNGQAELFYRPKSRMKRMAHRLGEKMLNKKLKDQKTPIPDTLYQELYDYVNHRLSHDLSD
EARALLPNVITKEVSHEIIKDRRFTSDKFLFHVPITLNYQAANSPSKFNQRVNAYLKEHP
ETPIIGIDRGERNLIYITVIDSTGKILEQRSLNTIQQFDYQKKLDNREKERVAARQAWSV
VGTIKDLKQGYLSQVIHEIVDLMIHYQAVVVLENLNFGFKSKRTGIAEKAVYQQFEKMLI
DKLNCLVLKDYPAEKVGGVLNPYQLTDQFTSFAKMGTQSGFLFYVPAPYTSKIDPLTGFV
DPFVWKTIKNHESRKHFLEGFDFLHYDVKTGDFILHFKMNRNLSFQRGLPGFMPAWDIVF
EKNETQFDAKGTPFIAGKRIVPVIENHRFTGRYRDLYPANELIALLEEKGIVFRDGSNIL
PKLLENDDSHAIDTMVALIRSVLQMRNSNAATGEDYINSPVRDLNGVCFDSRFQNPEWPM
DADANGAYHIALKGQLLLNHLKESKDLKLQNGISNQDWLAYIQELRN

Sequence of entity 3 (C), FASTA

>22FN_3 DNA (41-MER) (chains C)
AAGTGGAATGCCATGTGGGCTTAAAGGTGAATCCTTTATTAAT

Primary citation

DNA-guided CRISPR-Cas12a effectors for programmable RNA recognition and cleavage. Wu, X., Lam, W.H., Zhao, Z. et al. Nat Biotechnol (2026). DOI 10.1038/s41587-026-03120-5 · PubMed

Other PDB entries of the same protein (UniProt U2UMQ6 (AlphaFold model), which also has an AlphaFold model), best resolution first:

5XH6 2.0 Å, Crystal structure of the Acidaminococcus sp. BV3L6 Cpf1 RVR variant in complex with…
5XH7 2.0 Å, Crystal structure of the Acidaminococcus sp. BV3L6 Cpf1 RR variant in complex with crRNA…
9MK3 2.7 Å, Engineered AsCas12a (M537R, F870L)
5B43 2.8 Å, Crystal structure of Acidaminococcus sp. Cpf1 in complex with crRNA and target DNA
11VQ 3.18 Å, DNA-guided AsCas12a
5KK5 3.29 Å, AsCpf1(E993A)-crRNA-DNA ternary complex
8SFL 3.3 Å, WT CRISPR-Cas12a with a 15bp R-loop
8SFN 3.3 Å, WT CRISPR-Cas12a with a 16bp R-loop and nontarget strand in the RuvC active site.
8SFO 3.3 Å, WT CRISPR-Cas12a with a 20bp R-loop and nontarget strand in the RuvC active site.
8SFH 3.4 Å, WT CRISPR-Cas12a with a 5bp R-loop
9CJI 3.4 Å, Cas12a:gRNA:DNA (Acidaminococcus sp.) with 0 RNA:DNA base pairs, structure 2
8SFI 3.5 Å, WT CRISPR-Cas12a with a 8bp R-loop

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