2RTA

APOSTREPTAVIDIN, PH 2.97, SPACE GROUP I4122

Entity

Entity ID	Chain ID	Description	Type	Chain length	Formula weight	Number of molecules	DB Name (Accession)	Biological source	Descriptive keywords
1	A	STREPTAVIDIN	polymer	135	14181.3	1	UniProt (P22629) Pfam (PF01382) In PDB	Streptomyces avidinii
2	A	SULFATE ION	non-polymer		96.1	2	Chemie (SO4)
3		water	water		18.0	53	Chemie (HOH)

Contents of the asymmetric unit

Polymers	Number of chains	1
	Total formula weight	14181.3
Non-Polymers*	Number of molecules	2
	Total formula weight	192.1
All*	Total formula weight	14373.5

*Water molecules are not included.