4BX6

trans-divalent streptavidin

Entity

Entity ID	Chain ID	Description	Type	Chain length	Formula weight	Number of molecules	DB Name (Accession)	Biological source	Descriptive keywords
1	A, D (A, D)	STREPTAVIDIN	polymer	127	13250.3	2	UniProt (P22629) Pfam (PF01382)	STREPTOMYCES AVIDINII
2	B, C (B, C)	STREPTAVIDIN	polymer	133	14056.0	2	UniProt (P22629) Pfam (PF01382)	STREPTOMYCES AVIDINII
3	E, F, G (B, D)	(4S)-2-METHYL-2,4-PENTANEDIOL	non-polymer		118.2	3	Chemie (MPD)
4	H, I, J, K (A, B, C, D)	water	water		18.0	466	Chemie (HOH)

Sequence modifications

A, D: 13 - 139 (UniProt: P22629)

PDB	External Database	Details
Ala 23	Asn 47	engineered mutation
Asp 27	Ser 51	engineered mutation
Ala 45	Ser 69	engineered mutation

B, C: 13 - 139 (UniProt: P22629)

PDB	External Database	Details
Glu 140	-	expression tag
Glu 141	-	expression tag
Glu 142	-	expression tag
Glu 143	-	expression tag
Glu 144	-	expression tag
Glu 145	-	expression tag

Contents of the asymmetric unit

Polymers	Number of chains	4
	Total formula weight	54612.7
Non-Polymers*	Number of molecules	3
	Total formula weight	354.5
All*	Total formula weight	54967.2

*Water molecules are not included.