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Blurring the boundary between linear scaling QM, QM/MM and polarizable force fields
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Blurring the boundary between linear scaling QM, QM/MM and polarizable force fields
The Effec(ve Fragment Molecular Orbital Method
Jan H. Jensen and Casper Steinmann University of Copenhagen
Dmitri Fedorov AIST, Japan
JPC A 2010, 114, 8705 PLoS ONE 2012, 7:e41117 PLoS ONE 2012, 7:e44480 arxiv.org/abs/1212.6172
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The Fragment Molecular Orbital (FMO2) method (and most other fragmentaEon methods)
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The Fragment Molecular Orbital (FMO2) method (and most other fragmentaEon methods)
Many-‐body PolarizaEon:
Monomer SCF in the Coulomb field of all other monomers
Iterated to self-‐consistency
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The Fragment Molecular Orbital (FMO2) method (and most other fragmentaEon methods)
Non-‐Coulomb effects:
Dimer SCF in the Coulomb field of all other monomers
Iterated to self-‐consistency
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The Fragment Molecular Orbital (FMO2) method (and most other fragmentaEon methods)
Coulomb effects:
Coulomb energy in the Coulomb field of all other monomers
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The EffecEve Fragment Molecular Orbital (EFMO) method (Using ideas from the EffecSve Fragment PotenSal (EFP) method)
Monomer SCF in the gas phase
Extract mulSpoles and dipole polarizability
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The EffecEve Fragment Molecular Orbital (EFMO) method (Using ideas from the EffecSve Fragment PotenSal (EFP) method)
Many-‐body polarizaEon
Computed classically using induced dipoles for enSre system
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The EffecEve Fragment Molecular Orbital (EFMO) method (Using ideas from the EffecSve Fragment PotenSal (EFP) method)
Coulomb and Non-‐Coulomb effects
dimer SCF in the gas phase
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The EffecEve Fragment Molecular Orbital (EFMO) method (Using ideas from the EffecSve Fragment PotenSal (EFP) method)
Coulomb effects
Computed using staSc mulSpoles
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MP2 (DFT doesn’t scale well)
+ 0
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Covalent FragmentaEon (ElectrostaSc screening crucial)
11 PLoS ONE 2012, 7:e44480
Implemented in GAMESS With gradients
Trp cage (20 residues) 2 residues/fragment
EFMO FMO2 Error in energy -‐4.3 6.4 kcal/mol
MP2/6-‐31G(d) gradient 314 409 minutes 20 cores (most Sme spent in MP2 dimers)
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PLoS ONE 2012, 7:e44480
QM/”MM”
AcSve
Frozen
EEFMO = EA + EA /F + EF
EEFMO = EA0 + EAJ
0 − EA0 − EJ
0 − EIJPOL( )
J∈F
RI ,J ≤Rcut
∑ + EAJES
J∈F
RI ,J >Rcut
∑ + EtotPOL
h^p://arxiv.org/abs/1212.6172
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Proof-‐of-‐concept arxiv.org/abs/1212.6172
ONIOM: MP2/cc-‐pVDZ:EFMO-‐RHF/6-‐31G(d)
16 Å
ΔH ≠ = 18 vs 13 (exp)
4 days/path 80 CPUs
To Do MP2:RHF-‐D opSmizaSon
EFMO/PCM Flexible EFP/Polarizable “Force Field”
(EFMO sSll quite slow for large acSve regions)
EEFMO = EI0
I
N
∑ + EIJES + EIJ
XR /CT + EIJDisp( )
IJ
N
∑ + EtotPOL
EFMO GUI: FRAGIT.org (Mikael Ibsen)
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Funding: EU (IRENE collab program)
Thank You!
QuesEons Now?
QuesEons Later?
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hZp://proteinsandwavefuncEons.blogspot.com/2013/01/new-‐presentaEon-‐blurring-‐boundary.html
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