9YAQ

The structure of the cardiac native cross bridge in the rigor state, myosin heads bound to actin molecules 5 and 6.

Entity

Entity ID	Chain ID	Description	Type	Chain length	Formula weight	Number of molecules	DB Name (Accession)	Biological source	Descriptive keywords
1	A, B, C, D (A, B, C, D)	Actin, alpha cardiac muscle 1	polymer	377	42064.9	4	UniProt (B6VNT8) Pfam (PF00022)	Sus scrofa (pig)	Cardiac muscle alpha actin 1
2	E, F, G, H (E, F, G, H)	Tropomyosin alpha-1 chain	polymer	284	32762.7	4	UniProt (P42639) Pfam (PF00261)	Sus scrofa (pig)	Alpha-tropomyosin,Tropomyosin-1
3	I, P (I, P)	Troponin T2, cardiac type	polymer	285	33941.7	2	UniProt (A0A5G2Q8N0) Pfam (PF00992)	Sus scrofa (pig)
4	J, K (J, K)	Myosin-7	polymer	1935	223649.1	2	UniProt (P79293) Pfam (PF02736) Pfam (PF00063) Pfam (PF01576)	Sus scrofa (pig)	Myosin heavy chain 7,Myosin heavy chain slow isoform,MyHC-slow,Myosin heavy chain,cardiac muscle beta isoform,MyHC-beta
5	L, M (L, M)	Myosin light chain 3	polymer	196	21788.9	2	UniProt (F1SNW4)	Sus scrofa (pig)	Myosin light chain 1,slow-twitch muscle B/ventricular isoform
6	N (N)	Troponin C, slow skeletal and cardiac muscles	polymer	161	18433.5	1	UniProt (P63317) Pfam (PF13499) Pfam (PF13833)	Sus scrofa (pig)	TN-C
7	O (O)	Troponin I, cardiac muscle	polymer	211	24120.7	1	UniProt (A5X5T5)	Sus scrofa (pig)	Cardiac troponin I
8	Q, S, U, W (A, B, C, D)	ADENOSINE-5'-DIPHOSPHATE	non-polymer		427.2	4	Chemie (ADP)
9	R, T, V, X (A, B, C, D)	MAGNESIUM ION	non-polymer		24.3	4	Chemie (MG) PubChem (888)
10	AA, Y, Z (N)	CALCIUM ION	non-polymer		40.1	3	Chemie (CA) PubChem (271)

Contents of the asymmetric unit

Polymers	Number of chains	16
	Total formula weight	900623.8
Non-Polymers*	Number of molecules	11
	Total formula weight	1926.3
All*	Total formula weight	902550.1

*Water molecules are not included.