Literature summary for 1.7.2.1 extracted from

Hough, M.A.; Eady, R.R.; Hasnain, S.S.
Identification of the proton channel to the active site type 2 Cu center of nitrite reductase: structural and enzymatic properties of the His254Phe and Asn90Ser mutants (2008), Biochemistry, 47, 13547-13553.

Crystallization (Commentary)

Crystallization (Comment)	Organism
mutant H254F loaded with either Cu2+ or Zn2+, to 1.5 A and 1.85 A, respectively. Both structures are essentially identical. Structure of mutant N90S, to 1.6 A resolution. In both the native and mutant N90S structures, a surface Zn ion is present in each monomer, bridging the two monomers through the coordinating residues His165 and Asp167 of one monomer and Glu195 of the adjacent monomer. This Zn site is similar to that described previously in several NiR structures	Achromobacter xylosoxidans

Crystallization (Comment)

Organism

mutant H254F loaded with either Cu2+ or Zn2+, to 1.5 A and 1.85 A, respectively. Both structures are essentially identical. Structure of mutant N90S, to 1.6 A resolution. In both the native and mutant N90S structures, a surface Zn ion is present in each monomer, bridging the two monomers through the coordinating residues His165 and Asp167 of one monomer and Glu195 of the adjacent monomer. This Zn site is similar to that described previously in several NiR structures

Achromobacter xylosoxidans

Protein Variants

Protein Variants	Comment	Organism
H254F	full catalytic activity despite disruption of the primary proton channel. No change in apparent Km value for nitrite	Achromobacter xylosoxidans
N90S	disruption of H-bonding in the high-pH proton channel results in an 70% decrease in specific activity. No change in apparent Km value for nitrite	Achromobacter xylosoxidans

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism
0.034	-	nitrite	wild-type, pH 7.1	Achromobacter xylosoxidans
0.05	-	nitrite	mutant H254F, pH 7.1	Achromobacter xylosoxidans
0.05	-	nitrite	mutant N90S, pH 7.1	Achromobacter xylosoxidans

Metals/Ions

Metals/Ions	Comment	Organism	Structure
Zn2+	present on surface of each monomer, crystallization data	Achromobacter xylosoxidans

Organism

Organism	UniProt	Comment	Textmining
Achromobacter xylosoxidans	O68601	-	-

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg]	Specific Activity Maximum [µmol/min/mg]	Comment	Organism
82	-	mutant N90S, pH 7.1	Achromobacter xylosoxidans
123	-	mutant H254F, pH 7.1	Achromobacter xylosoxidans
240	-	wild-type, pH 7.1	Achromobacter xylosoxidans

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
nitrite + reduced azurin I	-	Achromobacter xylosoxidans	NO + azurin I	-	?