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Entry M0222    4.1.2.13    fructose-bisphosphate aldolase (Class I)

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Step 04

The phosphate of the bound intermediate deprotonates water, which in turn deprotonates Tyr363.

GIF of Reaction Step M0222.stg04


Comment: The C-terminal tyrosine is highly mobile and the temporary binding of the C-terminus expels one of the catalytic waters from the active site. The tyrosine is activated by sequential proton transfer through a conserved water molecule that is hydrogen-bonded to the iminium phosphate dianion that acts as a conjugate base. The tyrosine phenate anion is stabilised by Lys146. [2]



Mechanisms

Proton Transfer

Mechanism Components

Bond Formation
Bond Cleavage
Intermediate Formation
Proton Relay

Amino acids involved in the reaction step.

Amino Acid Location of Function Activity Function
Lys229 Side Chain reactant Covalently Attached
Hydrogen Bond Donor
Glu187 Side Chain spectator Electrostatic Stabiliser
Hydrogen Bond Acceptor
Polar Interaction
Glu189 Side Chain spectator Polar Interaction
Hydrogen Bond Acceptor
Electrostatic Stabiliser
Activator
Lys146 Side Chain spectator Hydrogen Bond Donor
Electrostatic Stabiliser
Ser300 Side Chain spectator Hydrogen Bond Acceptor
Hydrogen Bond Donor
Electrostatic Stabiliser
Asp33 Side Chain spectator Hydrogen Bond Acceptor
Electrostatic Stabiliser
Tyr363 Side Chain reactant Hydrogen Bond Donor
Proton Donor

Reactive Centre

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

View similar reactions in MACiE.


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