2NOW

An unusual twin-His arrangement in the pore of ammonia channels is essential for substrate conductance

Entity

Entity ID	Chain ID	Description	Type	Chain length	Formula weight	Number of molecules	DB Name (Accession)	Biological source	Descriptive keywords
1	A (A)	Ammonia channel	polymer	424	44442.7	1	UniProt (P69681) Pfam (PF00909)	Escherichia coli	Ammonia transporter
2	B, C (A)	SULFATE ION	non-polymer		96.1	2	Chemie (SO4)
3	D (A)	ACETATE ION	non-polymer		59.0	1	Chemie (ACT)
4	E (A)	GLYCEROL	non-polymer		92.1	1	Chemie (GOL)
5	F (A)	water	water		18.0	103	Chemie (HOH)

Sequence modifications

A: 1 - 406 (UniProt: P69681)

PDB	External Database	Details
Glu 168	His 190	engineered mutation
Asp 407	-	expression tag
Gln 408	-	expression tag
Ala 409	-	expression tag
Gln 410	-	expression tag
Gln 411	-	expression tag
Pro 412	-	expression tag
Ala 413	-	expression tag
Gln 414	-	expression tag
Ala 415	-	expression tag
Asp 416	-	expression tag
Leu 417	-	expression tag
Glu 418	-	expression tag
His 419	-	expression tag
His 420	-	expression tag
His 421	-	expression tag
His 422	-	expression tag
His 423	-	expression tag
His 424	-	expression tag

Contents of the asymmetric unit

Polymers	Number of chains	1
	Total formula weight	44442.7
Non-Polymers*	Number of molecules	4
	Total formula weight	343.3
All*	Total formula weight	44785.9

*Water molecules are not included.