6MC4

Crystal structure of a tetrameric DNA fold-back quadruplex

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, E...	DNA (5'-D(*CP*GP*TP*CP*AP*GP*GP*CP*G)-3')	polymer	9	2756.8	8		synthetic construct
2	A, C, D, E, F...	CALCIUM ION	non-polymer		40.1	10	Chemie (CA)
3	B	POTASSIUM ION	non-polymer		39.1	1	Chemie (K)
4		water	water		18.0	95	Chemie (HOH)

Contents of the asymmetric unit

Polymers	Number of chains	8
	Total formula weight	22054.5
Non-Polymers*	Number of molecules	11
	Total formula weight	439.9
All*	Total formula weight	22494.4

*Water molecules are not included.