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Entry M0276    1.7.99.4    nitrate reductase

Previous Step

Step 07

The Cys152 sulfur atom substitutes the water molecule coordinated to the molybdenum centre.

GIF of Reaction Step M0276.stg07


Comment: The lone pair of electrons on the bridging sulfur substitutes the coordinated water. Both sulfur atoms of the disulfide bond are coordinated to the metal.
In the absence of nitrate, the metal coordination sphere returns to its ground state.



Mechanisms

Intramolecular Nucleophilic Substitution

Mechanism Components

Bond Formation
Bond Cleavage
Cofactor Regenerated
Overall Product Formed
Enzyme Regenerated
Intermediate Terminated

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
Covalently Attached
Electrostatic Stabiliser
Metal Ligand
Nucleophile
Gly383A Main Chain Amide spectator Hydrogen Bond Acceptor
Met346A Side Chain spectator Electrostatic Stabiliser
Polar Non-polar interaction
Steric Role
Glu384A Side Chain spectator Not Active

Organic Cofactors involved in the reaction step

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

Metal Cofactors involved in Step 07

Metal Type Metal Identity Chain Activity Function
iron SF4 1801 A spectator Not Active
molybdenum MO 1802 A spectator Not Active
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-S
Mo-O
None
Mo
O
S

View similar reactions in MACiE.


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