9ZZK: Actin, alpha skeletal muscle

One Lmod2 and incoming actin at the pointed end of F-actin. Determined by electron microscopy at 4.06 Å resolution. Released 24 Jun 2026.

Method: Electron microscopy
Resolution: 4.06 Å
Organisms: Oryctolagus cuniculus, Homo sapiens
Chains: 7
Atoms: 18,791
Mol. weight: 316.91 kDa
Ligands: ADP, MG, ATP
Released: 24 Jun 2026

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

Secondary structure: helices and β-sheets

9ZZK contains 135 α-helices and 123 β-strands across 7 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, 20 β-strands

Element	Residues	Length	Sheet
β-strand	8-11	4	1
β-strand	16-21	6	1
β-strand	29-32	4	1
β-strand	35-38	4	2
β-strand	53-54	2	2
α-helix	55-57	3
α-helix	62-64	3
β-strand	65-68	4	2
β-strand	71-72	2	3
β-strand	75-76	2	3
α-helix	79-88	10
α-helix	89-93	5
β-strand	103-107	5	1
α-helix	113-125	13
β-strand	131-136	6	1
α-helix	137-144	8
β-strand	149-155	7	4
β-strand	160-166	7	4
β-strand	169	1	5
β-strand	170	1	4
α-helix	172-174	3
β-strand	176-178	3	4
α-helix	182-196	15
α-helix	206-215	10
α-helix	223-232	10
β-strand	238-241	4	6
β-strand	247-250	4	6
α-helix	253-256	4
α-helix	258-261	4
α-helix	264-266	3
α-helix	274-283	10
α-helix	290-294	5
β-strand	297-300	4	4
α-helix	303-305	3
α-helix	309-320	12
β-strand	329-330	2	4
α-helix	335-337	3
α-helix	338-346	9
β-strand	357-358	2	1
α-helix	359-364	6
α-helix	367-370	4

Chain B: 24 helices, 19 β-strands

Element	Residues	Length	Sheet
β-strand	8-12	5	7
β-strand	16-21	6	7
β-strand	29-32	4	7
β-strand	35-37	3	8
β-strand	53-54	2	8
α-helix	56-60	5
α-helix	62-64	3
β-strand	66-68	3	8
β-strand	71-72	2	9
β-strand	75-76	2	9
α-helix	80-87	8
α-helix	88-93	6
α-helix	98-100	3
β-strand	103-107	5	7
α-helix	113-121	9
α-helix	122-126	5
β-strand	131-136	6	7
α-helix	137-144	8
β-strand	150-155	6	10
β-strand	160-166	7	10
β-strand	169-170	2	10
α-helix	172-174	3
β-strand	176-178	3	10
α-helix	182-192	11
α-helix	203-216	14
α-helix	223-232	10
β-strand	238-241	4	11
β-strand	247-250	4	11
α-helix	253-256	4
α-helix	258-260	3
α-helix	264-266	3
α-helix	272-273	2
α-helix	274-283	10
β-strand	297-300	4	10
α-helix	303-305	3
α-helix	309-320	12
β-strand	329-330	2	10
α-helix	335-337	3
α-helix	338-346	9
α-helix	353-355	3
β-strand	357-358	2	7
α-helix	359-365	7
α-helix	369-373	5

Chain C: 22 helices, 21 β-strands

Element	Residues	Length	Sheet
β-strand	8-12	5	12
β-strand	16-21	6	12
β-strand	29-32	4	12
β-strand	35-38	4	13
β-strand	42	1	5
β-strand	53-54	2	13
α-helix	56-60	5
α-helix	62-64	3
β-strand	65-68	4	13
β-strand	71-72	2	14
β-strand	75-76	2	14
α-helix	80-87	8
α-helix	88-93	6
α-helix	98-100	3
β-strand	103-107	5	12
α-helix	113-125	13
β-strand	131-136	6	12
α-helix	137-145	9
β-strand	150-155	6	15
β-strand	160-165	6	15
β-strand	169	1	16
β-strand	170	1	15
α-helix	172-174	3
β-strand	176-178	3	15
α-helix	182-192	11
α-helix	193-196	4
α-helix	204-215	12
α-helix	223-232	10
β-strand	238-241	4	17
β-strand	247-250	4	17
α-helix	253-256	4
α-helix	258-261	4
α-helix	264-266	3
α-helix	274-284	11
α-helix	290-294	5
β-strand	297-301	5	15
α-helix	303-305	3
α-helix	309-320	12
β-strand	329-330	2	15
α-helix	338-346	9
β-strand	357-358	2	12
α-helix	359-365	7
α-helix	369-373	5

Chain D: 24 helices, 20 β-strands

Element	Residues	Length	Sheet
β-strand	8-12	5	18
β-strand	16-21	6	18
β-strand	29-32	4	18
β-strand	35-38	4	19
α-helix	41	1
β-strand	42	1	10
β-strand	53-54	2	19
α-helix	56-60	5
β-strand	65-68	4	19
β-strand	71-72	2	20
β-strand	75-76	2	20
α-helix	79-87	9
α-helix	88-93	6
α-helix	98-100	3
β-strand	103-107	5	18
α-helix	113-125	13
β-strand	131-136	6	18
α-helix	137-144	8
β-strand	150-155	6	21
β-strand	160-166	7	21
β-strand	169-170	2	21
α-helix	172-174	3
β-strand	176-178	3	21
α-helix	182-192	11
α-helix	203-216	14
α-helix	223-232	10
β-strand	238-241	4	22
β-strand	247-250	4	22
α-helix	253-256	4
α-helix	258-261	4
α-helix	264-266	3
α-helix	272-273	2
α-helix	274-283	10
α-helix	287-289	3
α-helix	290-294	5
β-strand	297-300	4	21
α-helix	303-305	3
α-helix	309-320	12
β-strand	329-330	2	21
α-helix	338-346	9
α-helix	350-354	5
β-strand	357-358	2	18
α-helix	359-365	7
α-helix	369-373	5

Chain E: 21 helices, 20 β-strands

Element	Residues	Length	Sheet
β-strand	8-12	5	23
β-strand	16-21	6	23
β-strand	29-32	4	23
β-strand	35-38	4	24
α-helix	41	1
β-strand	42	1	16
β-strand	53-54	2	24
α-helix	55-60	6
α-helix	62-64	3
β-strand	65-68	4	24
β-strand	71-72	2	25
β-strand	75-76	2	25
α-helix	79-87	9
α-helix	88-93	6
α-helix	98-100	3
β-strand	103-107	5	23
α-helix	113-125	13
β-strand	131-136	6	23
α-helix	137-145	9
β-strand	150-155	6	26
β-strand	160-166	7	26
β-strand	169-170	2	26
β-strand	176-178	3	26
α-helix	182-192	11
α-helix	206-216	11
α-helix	223-232	10
β-strand	238-241	4	27
β-strand	247-250	4	27
α-helix	253-256	4
α-helix	258-260	3
α-helix	264-266	3
α-helix	274-283	10
α-helix	290-294	5
β-strand	297-300	4	26
α-helix	303-305	3
α-helix	309-320	12
β-strand	329-330	2	26
α-helix	338-346	9
β-strand	357-358	2	23
α-helix	359-365	7
α-helix	369-373	5

Chain M: 6 helices, 5 β-strands

Element	Residues	Length	Sheet
α-helix	200-207	8
β-strand	215-217	3	28
α-helix	226-235	10
β-strand	244-246	3	28
α-helix	254-264	11
β-strand	272-274	3	28
α-helix	282-290	9
β-strand	300-302	3	28
α-helix	312-321	10
β-strand	330-332	3	28
α-helix	338-362	25

Chain O: 17 helices, 18 β-strands

Element	Residues	Length	Sheet
β-strand	8-11	4	29
β-strand	17-21	5	29
β-strand	29-31	3	29
β-strand	35-38	4	30
β-strand	53	1	30
β-strand	65-68	4	30
β-strand	72	1	31
β-strand	75	1	31
α-helix	79-88	10
α-helix	89-93	5
β-strand	103-107	5	29
α-helix	113-125	13
β-strand	131-136	6	29
α-helix	137-144	8
β-strand	150-155	6	32
β-strand	160-165	6	32
β-strand	176-178	3	32
α-helix	182-196	15
α-helix	206-216	11
α-helix	224-232	9
β-strand	238-241	4	33
β-strand	247-250	4	33
α-helix	252-254	3
α-helix	259-262	4
α-helix	264-266	3
α-helix	274-283	10
α-helix	290-294	5
β-strand	297-300	4	32
α-helix	309-320	12
β-strand	329-330	2	32
α-helix	338-347	10
β-strand	357-358	2	29
α-helix	359-365	7
α-helix	367-370	4
α-helix	371-374	4

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Actin, alpha skeletal muscle	A, B, C, D, E, O	protein	375	Oryctolagus cuniculus	P68135 (AlphaFold model)
Leiomodin-2	M	protein	556	Homo sapiens	Q6P5Q4 (AlphaFold model)

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

>9ZZK_1 Actin, alpha skeletal muscle (chains A, B, C, D, E, O)
DEDETTALVCDNGSGLVKAGFAGDDAPRAVFPSIVGRPRHQGVMVGMGQKDSYVGDEAQS
KRGILTLKYPIEHGIITNWDDMEKIWHHTFYNELRVAPEEHPTLLTEAPLNPKANREKMT
QIMFETFNVPAMYVAIQAVLSLYASGRTTGIVLDSGDGVTHNVPIYEGYALPHAIMRLDL
AGRDLTDYLMKILTERGYSFVTTAEREIVRDIKEKLCYVALDFENEMATAASSSSLEKSY
ELPDGQVITIGNERFRCPETLFQPSFIGMESAGIHETTYNSIMKCDIDIRKDLYANNVMS
GGTTMYPGIADRMQKEITALAPSTMKIKIIAPPERKYSVWIGGSILASLSTFQQMWITKQ
EYDEAGPSIVHRKCF

Sequence of entity 2 (M), FASTA

>9ZZK_2 Leiomodin-2 (chains M)
MHHHHHHSGMSTFGYRRGLSKYESIDEDELLASLSAEELKELERELEDIEPDRNLPVGLR
QKSLTEKTPTGTFSREALMAYWEKESQKLLEKERLGECGKVAEDKEESEEELIFTESNSE
VSEEVYTEEEEEESQEEEEEEDSDEEERTIETAKGINGTVNYDSVNSDNSKPKIFKSQIE
NINLTNGSNGRNTESPAAIHPCGNPTVIEDALDKIKSNDPDTTEVNLNNIENITTQTLTR
FAEALKDNTVVKTFSLANTHADDSAAMAIAEMLKVNEHITNVNVESNFITGKGILAIMRA
LQHNTVLTELRFHNQRHIMGSQVEMEIVKLLKENTTLLRLGYHFELPGPRMSMTSILTRN
MDKQRQKRLQEQKQQEGYDGGPNLRTKVWQRGTPSSSPYVSPRHSPWSSPKLPKKVQTVR
SRPLSPVATPPPPPPPPPPPPPSSQRLPPPPPPPPPPLPEKKLITRNIAEVIKQQESAQR
ALQNGQKKKKGKKVKKQPNSILKEIKNSLRSVQEKKMEDSSRPSTPQRSAHENLMEAIRG
SSIKQLKRVEVPEALR

Ligands and cofactors

ID	Name	Formula	Copies
ADP	Adenosine-5'-diphosphate	C10 H15 N5 O10 P2	5
MG	Magnesium ion	Mg	6
ATP	Adenosine-5'-triphosphate	C10 H16 N5 O13 P3	1

Primary citation

Leiomodin 2 is a processive pointed-end elongator of actin filaments. Biswas, S., Larrinaga, T.M., Choubey, S. et al. Nat Commun (2026) 17. DOI 10.1038/s41467-026-74809-z · PubMed

Other PDB entries of the same protein (UniProt P68135 (AlphaFold model), which also has an AlphaFold model), best resolution first:

4B1Y 1.29 Å, Structure of the Phactr1 RPEL-3 bound to G-actin
2FXU 1.35 Å, X-ray Structure of Bistramide A- Actin Complex at 1.35 A resolution.
4K41 1.4 Å, Crystal structure of actin in complex with marine macrolide kabiramide C
1QZ5 1.45 Å, Structure of rabbit actin in complex with kabiramide C
1WUA 1.45 Å, The structure of Aplyronine A-actin complex
2Q0U 1.45 Å, Structure of Pectenotoxin-2 and Latrunculin B Bound to Actin
2V52 1.45 Å, Structure of MAL-RPEL2 complexed to G-actin
3MN5 1.5 Å, Structures of actin-bound WH2 domains of Spire and the implication for filament nucleation
2PBD 1.5 Å, Ternary complex of profilin-actin with the poly-PRO-GAB domain of VASP*
5ZZA 1.53 Å, OdinProfilin/Rabbit Actin Complex
1J6Z 1.54 Å, Uncomplexed actin
1QZ6 1.6 Å, Structure of rabbit actin in complex with jaspisamide A

Browse structure collections

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