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Entry M0234    6.3.5.2    GMP synthase (glutamine-hydrolysing)

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Step 04

Ammonia is deprotonated by the phosphate of the intermediate, activating it for a nucleophilic attack on the intermediate, which liberates AMP and the GMP product.

GIF of Reaction Step M0234.stg04


Comment: Reaction occurs in the ATP pyrophosphatase domain (CATH 3.40.50.620). It is assumed that the phosphate acts as the general base, and that the magnesium ion stabilises the pentacoordinate transition state.



Mechanisms

Bimolecular Nucleophilic Substitution
Proton Transfer

Mechanism Components

Bond Cleavage
Bond Formation
Intermediate Terminated
Intermediate Collapse
Overall Product Formed

Amino acids involved in the reaction step.

Amino Acid Location of Function Activity Function
Lys381 Side Chain spectator Hydrogen Bond Donor
Asp239 Side Chain spectator Metal Ligand
Hydrogen Bond Acceptor

Metal Cofactors involved in Step 04

Metal Type Metal Identity Chain Activity Function
magnesium MG 530 B spectator Substrate Binding
Electrostatic Stabiliser

Reactive Centre

Bonds Formed Bonds Cleaved Bonds Changed in Order Atom Types Involved
C-N
O-H
C-O
N-H
None
C
H
N
O

View similar reactions in MACiE.


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