1TLF

UNPRECEDENTED QUATERNARY STRUCTURE OF E. COLI LAC REPRESSOR CORE TETRAMER: IMPLICATIONS FOR DNA LOOPING

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	LAC REPRESSOR	polymer	301	32154.7	4	UniProt (P03023) Pfam (PF13377) In PDB	Escherichia coli
2	A, B, C, D	ETHYL MERCURY ION	non-polymer		229.7	4	Chemie (EMC)
3	A, B, C, D	1-methylethyl 1-thio-beta-D-galactopyranoside	non-polymer		238.3	4	Chemie (IPT)

Contents of the asymmetric unit

Polymers	Number of chains	4
	Total formula weight	128618.8
Non-Polymers*	Number of molecules	8
	Total formula weight	1871.8
All*	Total formula weight	130490.6

*Water molecules are not included.