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Entry M0020    1.3.99.1    succinate dehydrogenase

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Step 02

FAD eliminates a hydride ion, which adds to fumarate with concomitant double bond rearrangement, the terminal carboxylate deprotonates His504.

GIF of Reaction Step M0020.stg02


Comment: The driving force of the reaction is from the perturbation of the acid group which is near the histidine group. This induces a dipole in the double bond which allows the reduction [1,2].



Mechanisms

Proton Transfer
Hydride Transfer
Aromatic Unimolecular Elimination by the conjugate base
Aromatic Bimolecular Nucleophilic Addition

Mechanism Components

Overall Reactant Used
Bond Cleavage
Bond Formation
Bond Order Change
Overall Product Formed
Intermediate Formation
Cofactor Regenerated

Amino acids involved in the reaction step.

Amino Acid Location of Function Activity Function
Arg544 Side Chain spectator Hydrogen Bond Donor
Electrostatic Stabiliser
His504 Side Chain reactant Hydrogen Bond Donor
Proton Donor
His365 Side Chain spectator Hydrogen Bond Donor
Electrostatic Stabiliser
Arg402 Side Chain spectator Hydrogen Bond Donor
Electrostatic Stabiliser
Arg381 Side Chain spectator Hydrogen Bond Acceptor
Hydrogen Bond Donor
Glu378 Side Chain spectator Hydrogen Bond Acceptor

Organic Cofactors involved in the reaction step

Cofactor Type Cofactor Activity Function
FAD FAD805 reactant van der Waals interaction
Hydride Donor
Hydrogen Bond Donor

Metal Cofactors involved in Step 02

Metal Type Metal Identity Chain Activity Function
iron HEC 801 _ spectator Not Active
iron HEC 802 _ spectator Not Active
iron HEC 803 _ spectator Not Active
iron HEC 804 _ spectator Not Active

Reactive Centre

Bonds Formed Bonds Cleaved Bonds Changed in Order Atom Types Involved
C-H
O-H
N-H
N-H
The C-C bond changes from a single to double bond
The C-N bond changes from a single to double bond
The C-N bond changes from a single to double bond
The C-C bond changes from a double to single bond
The C-C bond changes from a double to single bond
The C-O bond changes from a double to single bond
C
H
N
O

View similar reactions in MACiE.


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