1SWD

APO-CORE-STREPTAVIDIN IN COMPLEX WITH BIOTIN (TWO UNOCCUPIED BINDING SITES) AT PH 4.5

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	STREPTAVIDIN	polymer	127	13281.3	4	UniProt (P22629) Pfam (PF01382) In PDB	Streptomyces avidinii	CORE STREPTAVIDIN
2	A, D	BIOTIN	non-polymer		244.3	2	Chemie (BTN)
3		water	water		18.0	234	Chemie (HOH)

Contents of the asymmetric unit

Polymers	Number of chains	4
	Total formula weight	53125.3
Non-Polymers*	Number of molecules	2
	Total formula weight	488.6
All*	Total formula weight	53614.0

*Water molecules are not included.