Exploring the interaction of SV2A with racetams using homology modelling, molecular dynamics and site-directed mutagenesis.

The putative Major Facilitator Superfamily (MFS) transporter, SV2A, is the target for levetiracetam (LEV), which is a successful anti-epileptic drug. Furthermore, SV2A knock out mice display a severe seizure phenotype and die after a few weeks. Despite this, the mode of action of LEV is not known at...

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Main Authors: Joanna Lee, Veronique Daniels, Zara A Sands, Florence Lebon, Jiye Shi, Philip C Biggin
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2015-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC4333566?pdf=render
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author Joanna Lee
Veronique Daniels
Zara A Sands
Florence Lebon
Jiye Shi
Philip C Biggin
author_facet Joanna Lee
Veronique Daniels
Zara A Sands
Florence Lebon
Jiye Shi
Philip C Biggin
author_sort Joanna Lee
collection DOAJ
description The putative Major Facilitator Superfamily (MFS) transporter, SV2A, is the target for levetiracetam (LEV), which is a successful anti-epileptic drug. Furthermore, SV2A knock out mice display a severe seizure phenotype and die after a few weeks. Despite this, the mode of action of LEV is not known at the molecular level. It would be extremely desirable to understand this more fully in order to aid the design of improved anti-epileptic compounds. Since there is no structure for SV2A, homology modelling can provide insight into the ligand-binding site. However, it is not a trivial process to build such models, since SV2A has low sequence identity to those MFS transporters whose structures are known. A further level of complexity is added by the fact that it is not known which conformational state of the receptor LEV binds to, as multiple conformational states have been inferred by tomography and ligand binding assays or indeed, if binding is exclusive to a single state. Here, we explore models of both the inward and outward facing conformational states of SV2A (according to the alternating access mechanism for MFS transporters). We use a sequence conservation analysis to help guide the homology modelling process and generate the models, which we assess further with Molecular Dynamics (MD). By comparing the MD results in conjunction with docking and simulation of a LEV-analogue used in radioligand binding assays, we were able to suggest further residues that line the binding pocket. These were confirmed experimentally. In particular, mutation of D670 leads to a complete loss of binding. The results shed light on the way LEV analogues may interact with SV2A and may help with the on-going design of improved anti-epileptic compounds.
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spelling doaj.art-ae42f1295e90453ba5296467551df3bc2022-12-22T01:54:58ZengPublic Library of Science (PLoS)PLoS ONE1932-62032015-01-01102e011658910.1371/journal.pone.0116589Exploring the interaction of SV2A with racetams using homology modelling, molecular dynamics and site-directed mutagenesis.Joanna LeeVeronique DanielsZara A SandsFlorence LebonJiye ShiPhilip C BigginThe putative Major Facilitator Superfamily (MFS) transporter, SV2A, is the target for levetiracetam (LEV), which is a successful anti-epileptic drug. Furthermore, SV2A knock out mice display a severe seizure phenotype and die after a few weeks. Despite this, the mode of action of LEV is not known at the molecular level. It would be extremely desirable to understand this more fully in order to aid the design of improved anti-epileptic compounds. Since there is no structure for SV2A, homology modelling can provide insight into the ligand-binding site. However, it is not a trivial process to build such models, since SV2A has low sequence identity to those MFS transporters whose structures are known. A further level of complexity is added by the fact that it is not known which conformational state of the receptor LEV binds to, as multiple conformational states have been inferred by tomography and ligand binding assays or indeed, if binding is exclusive to a single state. Here, we explore models of both the inward and outward facing conformational states of SV2A (according to the alternating access mechanism for MFS transporters). We use a sequence conservation analysis to help guide the homology modelling process and generate the models, which we assess further with Molecular Dynamics (MD). By comparing the MD results in conjunction with docking and simulation of a LEV-analogue used in radioligand binding assays, we were able to suggest further residues that line the binding pocket. These were confirmed experimentally. In particular, mutation of D670 leads to a complete loss of binding. The results shed light on the way LEV analogues may interact with SV2A and may help with the on-going design of improved anti-epileptic compounds.http://europepmc.org/articles/PMC4333566?pdf=render
spellingShingle Joanna Lee
Veronique Daniels
Zara A Sands
Florence Lebon
Jiye Shi
Philip C Biggin
Exploring the interaction of SV2A with racetams using homology modelling, molecular dynamics and site-directed mutagenesis.
PLoS ONE
title Exploring the interaction of SV2A with racetams using homology modelling, molecular dynamics and site-directed mutagenesis.
title_full Exploring the interaction of SV2A with racetams using homology modelling, molecular dynamics and site-directed mutagenesis.
title_fullStr Exploring the interaction of SV2A with racetams using homology modelling, molecular dynamics and site-directed mutagenesis.
title_full_unstemmed Exploring the interaction of SV2A with racetams using homology modelling, molecular dynamics and site-directed mutagenesis.
title_short Exploring the interaction of SV2A with racetams using homology modelling, molecular dynamics and site-directed mutagenesis.
title_sort exploring the interaction of sv2a with racetams using homology modelling molecular dynamics and site directed mutagenesis
url http://europepmc.org/articles/PMC4333566?pdf=render
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