2NTU

Bacteriorhodopsin, wild type, before illumination

Entity

Entity ID	Chain ID	Description	Type	Chain length	Formula weight	Number of molecules	DB Name (Accession)	Biological source	Descriptive keywords
1	A	Bacteriorhodopsin	polymer	249	26929.5	1	UniProt (P02945) Pfam (PF01036) In PDB	Halobacterium salinarum	BR
2	A	RETINAL	non-polymer		284.4	1	Chemie (RET)
3		water	water		18.0	23	Chemie (HOH)

Contents of the asymmetric unit

Polymers	Number of chains	1
	Total formula weight	26929.5
Non-Polymers*	Number of molecules	1
	Total formula weight	284.4
All*	Total formula weight	27213.9

*Water molecules are not included.