11DD: PDB entry 11DD

Human Slo1-Charybdotoxin complex under divalent chelated condition. Determined by electron microscopy at 2.9 Å resolution. Released 23 Sept 2026.

Method: Electron microscopy
Resolution: 2.9 Å
Organisms: Homo sapiens, Leiurus quinquestriatus
Chains: 5
Atoms: 31,299
Mol. weight: 556.15 kDa
Ligands: AJP, LBN
Released: 23 Sept 2026

Explore 11DD in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

11DD contains 206 α-helices and 133 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: 52 helices, 32 β-strands

Element	Residues	Length	Sheet
α-helix	22-45	24
α-helix	94-104	11
α-helix	110-133	24
β-strand	139-141	3	1
α-helix	144-146	3
α-helix	149-170	22
α-helix	181-187	7
α-helix	190-199	10
β-strand	201-203	3	1
α-helix	207-216	10
α-helix	217-223	7
α-helix	230-259	30
α-helix	262-264	3
α-helix	274-285	12
α-helix	298-325	28
β-strand	343-348	6	2
α-helix	353-363	11
β-strand	373-379	7	2
α-helix	382-383	2
α-helix	385-393	9
β-strand	398-402	5	2
α-helix	408-413	6
α-helix	416-418	3
β-strand	421-424	4	2
α-helix	433-450	18
β-strand	455-460	6	2
α-helix	466-471	6
α-helix	477-479	3
β-strand	482-485	4	2
α-helix	486-499	14
α-helix	503-510	8
α-helix	524-532	9
β-strand	535-540	6	3
α-helix	541-542	2
α-helix	543-545	3
β-strand	549	1	4
α-helix	550-559	10
β-strand	564-570	7	3
β-strand	578-581	4	3
β-strand	588	1	4
β-strand	594-599	6	3
α-helix	602-606	5
α-helix	607-610	4
β-strand	686-687	2	5
β-strand	693	1	5
α-helix	700-702	3
β-strand	704	1	6
α-helix	707-712	6
β-strand	719-724	6	6
α-helix	730-731	2
α-helix	735-738	4
α-helix	740-742	3
α-helix	751-753	3
β-strand	754-758	5	6
α-helix	760-766	7
α-helix	767-769	3
β-strand	776-780	5	6
α-helix	786-792	7
α-helix	794-796	3
β-strand	799-804	6	6
α-helix	818-829	12
β-strand	831	1	7
β-strand	872	1	7
α-helix	873-875	3
β-strand	878-882	5	6
α-helix	888-891	4
α-helix	903-905	3
α-helix	907-910	4
β-strand	914-916	3	6
α-helix	918-929	12
α-helix	931-941	11
α-helix	947-956	10
β-strand	961-962	2	5
α-helix	966-970	5
β-strand	976-981	6	8
β-strand	995	1	9
α-helix	996-1006	11
β-strand	1010-1017	8	8
α-helix	1018-1020	3
β-strand	1031-1035	5	8
α-helix	1041	1
β-strand	1042	1	9
α-helix	1043	1
β-strand	1047-1053	7	8

Chain B: 53 helices, 32 β-strands

Element	Residues	Length	Sheet
α-helix	22-45	24
α-helix	94-104	11
α-helix	110-133	24
β-strand	139-141	3	10
α-helix	149-169	21
α-helix	174-178	5
α-helix	181-187	7
α-helix	191-199	9
β-strand	201-203	3	10
α-helix	207-216	10
α-helix	217-223	7
α-helix	230-259	30
α-helix	262-264	3
α-helix	274-285	12
α-helix	298-326	29
β-strand	343-349	7	11
α-helix	353-363	11
β-strand	373-379	7	11
α-helix	385-393	9
β-strand	398-402	5	11
α-helix	408-413	6
α-helix	416-418	3
β-strand	421-425	5	11
α-helix	433-450	18
β-strand	455-460	6	11
α-helix	463-471	9
α-helix	477-479	3
β-strand	482-485	4	11
α-helix	486-499	14
α-helix	503-510	8
α-helix	524-532	9
β-strand	535-540	6	12
α-helix	541-542	2
α-helix	543-545	3
β-strand	549	1	13
α-helix	550-556	7
α-helix	557-561	5
β-strand	564-570	7	12
β-strand	578-581	4	12
β-strand	588	1	13
β-strand	594-599	6	12
α-helix	602-604	3
α-helix	606-609	4
β-strand	686-687	2	14
β-strand	693	1	14
α-helix	700-702	3
β-strand	704	1	15
α-helix	707-712	6
β-strand	719-724	6	15
α-helix	729-731	3
α-helix	735-738	4
α-helix	739-742	4
α-helix	748-750	3
α-helix	751-753	3
β-strand	754-758	5	15
α-helix	760-766	7
α-helix	767-769	3
β-strand	776-780	5	15
α-helix	786-791	6
α-helix	794-796	3
β-strand	799-804	6	15
α-helix	814-817	4
α-helix	820-827	8
β-strand	831	1	16
β-strand	872	1	16
α-helix	873-875	3
β-strand	878-882	5	15
α-helix	886-890	5
α-helix	903-905	3
α-helix	907-910	4
β-strand	914-916	3	15
α-helix	918-929	12
α-helix	932-941	10
α-helix	947-956	10
β-strand	961-962	2	14
α-helix	966-970	5
β-strand	976-981	6	17
β-strand	995	1	18
α-helix	996-1007	12
β-strand	1010-1017	8	17
α-helix	1018-1020	3
β-strand	1031-1035	5	17
β-strand	1042	1	18
β-strand	1047-1053	7	17
α-helix	1054-1055	2

Chain C: 51 helices, 32 β-strands

Element	Residues	Length	Sheet
α-helix	22-45	24
α-helix	94-104	11
α-helix	110-133	24
β-strand	139-141	3	19
α-helix	149-169	21
α-helix	174-178	5
α-helix	181-187	7
α-helix	191-199	9
β-strand	201-203	3	19
α-helix	207-216	10
α-helix	217-223	7
α-helix	231-259	29
α-helix	262-264	3
α-helix	274-285	12
α-helix	298-325	28
α-helix	336-338	3
β-strand	343-348	6	20
α-helix	353-363	11
β-strand	373-379	7	20
α-helix	385-393	9
β-strand	398-402	5	20
α-helix	408-413	6
β-strand	421-424	4	20
α-helix	433-450	18
β-strand	455-460	6	20
α-helix	463-471	9
β-strand	482-485	4	20
α-helix	486-499	14
α-helix	503-510	8
α-helix	524-532	9
β-strand	535-540	6	21
α-helix	541-542	2
α-helix	543-545	3
β-strand	549	1	22
α-helix	550-559	10
β-strand	564-570	7	21
β-strand	578-581	4	21
β-strand	588	1	22
β-strand	594-599	6	21
α-helix	602-604	3
α-helix	606-609	4
β-strand	686-687	2	23
β-strand	693	1	23
α-helix	700-702	3
β-strand	704	1	24
α-helix	707-712	6
β-strand	719-724	6	24
α-helix	730-731	2
α-helix	735-738	4
α-helix	740-742	3
α-helix	748-750	3
α-helix	751-753	3
β-strand	754-757	4	24
α-helix	760-766	7
α-helix	767-769	3
β-strand	776-779	4	24
α-helix	786-791	6
α-helix	794-796	3
β-strand	799-804	6	24
α-helix	814-817	4
α-helix	818-827	10
β-strand	831	1	25
β-strand	872	1	25
α-helix	873-875	3
β-strand	878-882	5	24
α-helix	885-887	3
α-helix	889-891	3
α-helix	903-905	3
α-helix	907-910	4
β-strand	914-916	3	24
α-helix	918-929	12
α-helix	932-941	10
α-helix	947-956	10
β-strand	961-962	2	23
α-helix	966-970	5
β-strand	976-981	6	26
β-strand	995	1	27
α-helix	996-1007	12
β-strand	1010-1017	8	26
α-helix	1018-1020	3
β-strand	1031-1035	5	26
β-strand	1042	1	27
β-strand	1047-1053	7	26

Chain D: 49 helices, 34 β-strands

Element	Residues	Length	Sheet
α-helix	22-45	24
α-helix	94-104	11
α-helix	110-133	24
β-strand	139-141	3	28
α-helix	148-168	21
α-helix	174-177	4
α-helix	181-187	7
α-helix	190-199	10
β-strand	201-203	3	28
α-helix	207-216	10
α-helix	217-223	7
α-helix	230-259	30
α-helix	262-264	3
α-helix	274-285	12
α-helix	298-326	29
α-helix	336-338	3
β-strand	343-349	7	29
α-helix	353-363	11
β-strand	373-379	7	29
α-helix	382-383	2
α-helix	385-393	9
β-strand	398-402	5	29
α-helix	408-413	6
β-strand	421-425	5	29
α-helix	433-450	18
β-strand	455-460	6	29
α-helix	464-471	8
α-helix	477-479	3
β-strand	482-485	4	29
α-helix	486-499	14
α-helix	503-510	8
α-helix	524-532	9
β-strand	535-540	6	30
α-helix	541-542	2
α-helix	543-545	3
β-strand	549	1	31
α-helix	550-559	10
β-strand	564-570	7	30
β-strand	578-581	4	30
β-strand	588	1	31
β-strand	594-599	6	30
α-helix	602-604	3
α-helix	606-609	4
β-strand	686-687	2	32
β-strand	692	1	33
β-strand	693	1	32
α-helix	700-702	3
β-strand	704	1	34
α-helix	707-712	6
β-strand	719-724	6	34
α-helix	730-731	2
α-helix	735-738	4
α-helix	740-742	3
β-strand	743	1	33
α-helix	751-753	3
β-strand	754-758	5	34
α-helix	760-766	7
α-helix	767-769	3
β-strand	776-780	5	34
α-helix	786-791	6
α-helix	794-796	3
β-strand	799-804	6	34
α-helix	820-828	9
β-strand	831	1	35
β-strand	872	1	35
α-helix	873-875	3
β-strand	878-882	5	34
α-helix	885-891	7
α-helix	907-910	4
β-strand	914-916	3	34
α-helix	918-929	12
α-helix	932-942	11
α-helix	947-956	10
β-strand	961-962	2	32
α-helix	966-970	5
β-strand	976-981	6	36
β-strand	995	1	37
α-helix	996-1007	12
β-strand	1010-1017	8	36
β-strand	1031-1035	5	36
β-strand	1042	1	37
β-strand	1047-1053	7	36
α-helix	1054-1055	2

Chain Y: 1 helix, 3 β-strands

Element	Residues	Length	Sheet
β-strand	2-6	5	38
α-helix	13-21	9
β-strand	27-29	3	38
β-strand	32-34	3	38

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Calcium-activated potassium channel subunit alpha-1	A, B, C, D	protein	1065	Homo sapiens	Q12791 (AlphaFold model)
Potassium channel toxin alpha-KTx 1.1	Y	protein	37	Leiurus quinquestriatus	P13487 (AlphaFold model)

Sequence of entity 1 (A, B, C, D), FASTA

>11DD_1 Calcium-activated potassium channel subunit alpha-1 (chains A, B, C, D)
MDALIIPVTMEVPCDSRGQRMWWAFLASSMVTFFGGLFIILLWRTLKYLWTVCCHCGGKT
KEAQKINNGSSQADGTLKPVDEKEEAVAAEVGWMTSVKDWAGVMISAQTLTGRVLVVLVF
ALSIGALVIYFIDSSNPIESCQNFYKDFTLQIDMAFNVFFLLYFGLRFIAANDKLWFWLE
VNSVVDFFTVPPVFVSVYLNRSWLGLRFLRALRLIQFSEILQFLNILKTSNSIKLVNLLS
IFISTWLTAAGFIHLVENSGDPWENFQNNQALTYWECVYLLMVTMSTVGYGDVYAKTTLG
RLFMVFFILGGLAMFASYVPEIIELIGNRKKYGGSYSAVSGRKHIVVCGHITLESVSNFL
KDFLHKDRDDVNVEIVFLHNISPNLELEALFKRHFTQVEFYQGSVLNPHDLARVKIESAD
ACLILANKYCADPDAEDASNIMRVISIKNYHPKIRIITQMLQYHNKAHLLNIPSWNWKEG
DDAICLAELKLGFIAQSCLAQGLSTMLANLFSMRSFIKIEEDTWQKYYLEGVSNEMYTEY
LSSAFVGLSFPTVCELCFVKLKLLMIAIEYKSANRESRILINPGNHLKIQEGTLGFFIAS
DAKEVKRAFFYCKACHDDITDPKRIKKCGCKRLEDEQPSTLSPKKKQRNGGMRNSPNTSP
KLMRHDPLLIPGNDQIDNMDSNVKKYDSTGMFHWCAPKEIEKVILTRSEAAMTVLSGHVV
VCIFGDVSSALIGLRNLVMPLRASNFHYHELKHIVFVGSIEYLKREWETLHNFPKVSILP
GTPLSRADLRAVNINLCDMCVILSANQNNIDDTSLQDKECILASLNIKSMQFDDSIGVLQ
ANSQGFTPPGMDRSSPDNSPVHGMLRQPSITTGVNIPIITELVNDTNVQFLDQDDDDDPD
TELYLTQPFACGTAFAVSVLDSLMSATYFNDNILTLIRTLVTGGATPELEALIAEENALR
GGYSTPQTLANRDRCRVAQLALLDGPFADLGDGGCYGDLFCKALKTYNMLCFGIYRLRDA
HLSTPSQCTKRYVITNPPYEFELVPTDLIFCLMQFDSNSLEVLFQ

Sequence of entity 2 (Y), FASTA

>11DD_2 Potassium channel toxin alpha-KTx 1.1 (chains Y)
QFTNVSCTTSKECWSVCQRLHNTSRGKCMNKKCRCYS

Ligands and cofactors

ID	Name	Formula	Copies
AJP	Digitonin	C56 H92 O29	36
LBN	1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine	C42 H82 N O8 P	36

Water and common crystallization additives (K) are not listed.

Primary citation

Structural underpinnings of human Slo1 inhibition by scorpion and fungal toxins. Kallure, G.S., Pal, K., Prather, G.W. et al. Proc Natl Acad Sci U S A (2026) 123:e2606537123-e2606537123. DOI 10.1073/pnas.2606537123 · PubMed

Other PDB entries of the same protein (UniProt Q12791 (AlphaFold model), which also has an AlphaFold model), best resolution first:

6V5A 2.0 Å, Crystal structure of the human BK channel gating ring L390P mutant
8V60 2.43 Å, F315A mutant of human Slo1 in presence of EDTA - resting VSD
11DA 2.57 Å, Human Slo1-PenitremA complex under divalent chelated condition - full model
9CZM 2.57 Å, Ca2+ bound open-inactivated hSlo1 + beta2N-beta4 channel in nanodisc.
11DC 2.58 Å, Human Slo1-PenitremA complex under divalent chelated condition - gating-ring masked out
11CZ 2.6 Å, Human Slo1-paxilline complex under divalent chelated condition - full model
8V64 2.6 Å, RCK1-RCK2 double mutant of human Slo1 in presence of EDTA - resting VSD
8GHF 2.7 Å, cryo-EM structure of hSlo1 in plasma membrane vesicles
11DB 2.71 Å, Human Slo1-Paxilline complex under divalent chelated condition - gating-ring masked
8V63 2.72 Å, R207A mutant of human Slo1 in presence of EDTA - activated VSD
9JO3 2.8 Å, Cryo-EM structure of human BKca channel-compound 10b complex
8VAZ 2.82 Å, Structure of human Slo1 and human LRRC26 in EDTA - LRRD masked

Browse structure collections

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