john mitchell bioinformatics chemoinformatics computational chemistry theoretical chemistry
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John Mitchell
BioinformaticsChemoinformatics
Computational ChemistryTheoretical Chemistry
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Mitchell group – BSRC & EaStCHEM School of ChemistryPurdie Building rooms 150 &152
Lazaros Mavridis Ava Sih-Yu Chen Rosanna Alderson
Neetika Nath James Mc Donagh Luna De Ferrari
Mechanism, Annotation and Classification in Enzymes.http://www.ebi.ac.uk/thornton-srv/databases/MACiE/
MACiE Database
The EC Classification
Reaction direction arbitrary
Cofactors and active site residues ignored
Doesn’t deal with structural and sequence information
However, it was never intended to do so
Deals with overall reaction, not mechanism
A New Representation of Enzyme Reactions?
Should be complementary to, but distinct from, the EC system
Should take into account:
Reaction Mechanism
Structure
Sequence
Active Site residues
Cofactors
Need a database of enzyme mechanisms
Mechanism, Annotation and Classification in Enzymes.http://www.ebi.ac.uk/thornton-srv/databases/MACiE/
MACiE Database
EC is not Everything
• Different mechanisms can occur with exactly the same EC number.
• MACiE has six beta-lactamases, all with different mechanisms but the same overall reaction.
EC Coverage of MACiE
Representative – based on a non-homologous dataset,and chosen to represent each available EC sub-subclass.
Structures exist for: 6 EC 1.-.-.- 61 EC 1.2.-.- 204 EC 1.2.3.-1776 EC 1.2.3.4
MACiE covers: 6 EC 1.-.-.- 57 EC 1.2.-.- 183 EC 1.2.3.- 321 EC 1.2.3.4
Coverage of MACiE
Representative – based on a non-homologous dataset,and chosen to represent each available EC sub-subclass.
Repertoire of Enzyme Catalysis
G.L. Holliday et al., J. Molec. Biol., 372, 1261-1277 (2007)G.L. Holliday et al., J. Molec. Biol., 390, 560-577 (2009)
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Reaction Types
Num
ber
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ste
ps in M
ACiE
Protontransfer
AdN2 E1 SN2 E2 Radicalreaction
Tautom. Others
Repertoire of Enzyme Catalysis
Repertoire of Enzyme Catalysis
We do see a few steps corresponding to well-known organic reactions; but these are the exception.
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Data sources
EnzML: Multi-label prediction of enzyme classes using InterPro signatures,L. De Ferrari et al. BMC Bioinformatics 2012, 13:61
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Predicting enzyme mechanism from Sequence
M0243 pyridoxine5'-phosphatesynthase
(EC 2.6.99.2)
M0243 pyridoxine5'-phosphatesynthase
(EC 2.6.99.2)
Moonlighting: A starting point for evolving
a new catalytic function!
Main reaction Minor side reaction
Enzyme Evolution
Investigating the apparent independent evolutionary origins of the B1 & B3 metallo- beta-lactamases at the chemical catalytic level
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Nitrogen-Oxygen Distance Distribu-tion
DIstance/ Angstroms
Num
ber o
bser
ved
Protein-Ligand Affinity Prediction: Scoring Functions
Prediction of Off-target Activities and Side Effects• Phospholipidosis; hERG blockade; Doping in sport; Polypharmacology