1ZT9

E. coli trp repressor, tetragonal crystal form

Entity

Entity ID	Chain ID	Description	Type	Chain length	Formula weight	Number of molecules	DB Name (Accession)	Biological source	Descriptive keywords
1	A, B, D, E	Trp operon repressor	polymer	107	12238.9	4	UniProt (P0A881) Pfam (PF01371) In PDB	Escherichia coli
2	A, B, D, E	SULFATE ION	non-polymer		96.1	8	Chemie (SO4)
3	A, B, D, E	TRYPTOPHAN	non-polymer		204.2	4	Chemie (TRP)
4		water	water		18.0	558	Chemie (HOH)

Contents of the asymmetric unit

Polymers	Number of chains	4
	Total formula weight	48955.7
Non-Polymers*	Number of molecules	12
	Total formula weight	1585.4
All*	Total formula weight	50541.1

*Water molecules are not included.