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Entry M0276    1.7.99.4    nitrate reductase

Next Step

Step 01

The nitrate oxyanion attacks the molybdenum coordination in a displacement reaction, eliminating the Cys152 sulfur which results in the formation of a disulfide bridge within the coordination sphere.

GIF of Reaction Step M0276.stg01


Comment: Physiological conditions allow an equilibrium between Mo(V) and Mo(VI) to exist [3]. The conformational change adopted by the coordination sphere on addition of the nitrate molecule is stabilised by the steric bulk and electronic charge delocalisation resulting from the position of Met308 and Met141 [1].



Mechanisms

Bimolecular Nucleophilic Substitution

Mechanism Components

Metal Coordination
Intermediate Formation
Metal De-coordination
Overall Reactant Used
Bond Formation
Bond Cleavage
Cofactor Used

Amino acids involved in the reaction step.

Amino Acid Location of Function Activity Function
Met153A Side Chain spectator Electrostatic Stabiliser
Polar Non-polar interaction
Steric Role
Lys56A Side Chain spectator Hydrogen Bond Donor
Cys152 Side Chain reactant Activator
Electrofuge
Covalently Attached
Gly383A Main Chain Amide spectator Electrostatic Stabiliser
Hydrogen Bond Acceptor
Met346A Side Chain spectator Electrostatic Stabiliser
Polar Non-polar interaction
Steric Role
Glu384A Side Chain spectator Electrostatic Stabiliser
Hydrogen Bond Acceptor

Organic Cofactors involved in the reaction step

Cofactor Type Cofactor Activity Function
Molybdopterin guanosine dinucleotide MGD1803A spectator Electrostatic Stabiliser
Hydrogen Bond Acceptor
Metal Ligand
Activator
Molybdopterin guanosine dinucleotide MGD1804A spectator Electrostatic Stabiliser
Hydrogen Bond Acceptor
Metal Ligand
Activator

Metal Cofactors involved in Step 01

Metal Type Metal Identity Chain Activity Function
iron SF4 1801 A spectator Not Active
molybdenum MO 1802 A spectator Substrate Binding
iron HEC 1128 B spectator Not Active
iron HEC 1129 B spectator Not Active

Reactive Centre

Bonds Formed Bonds Cleaved Bonds Changed in Order Atom Types Involved
Mo-O
Mo-S
None
Mo
O
S

View similar reactions in MACiE.


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