In silico docking of forchlorfenuron (FCF) to septins suggests that FCF interferes with GTP binding.

Septins are GTP-binding proteins that form cytoskeleton-like filaments, which are essential for many functions in eukaryotic organisms. Small molecule compounds that disrupt septin filament assembly are valuable tools for dissecting septin functions with high temporal control. To date, forchlorfenur...

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Main Authors: Dimitrios Angelis, Eva Pauline Karasmanis, Xiaobo Bai, Elias T Spiliotis
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2014-01-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0096390&type=printable
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author Dimitrios Angelis
Eva Pauline Karasmanis
Xiaobo Bai
Elias T Spiliotis
author_facet Dimitrios Angelis
Eva Pauline Karasmanis
Xiaobo Bai
Elias T Spiliotis
author_sort Dimitrios Angelis
collection DOAJ
description Septins are GTP-binding proteins that form cytoskeleton-like filaments, which are essential for many functions in eukaryotic organisms. Small molecule compounds that disrupt septin filament assembly are valuable tools for dissecting septin functions with high temporal control. To date, forchlorfenuron (FCF) is the only compound known to affect septin assembly and functions. FCF dampens the dynamics of septin assembly inducing the formation of enlarged stable polymers, but the underlying mechanism of action is unknown. To investigate how FCF binds and affects septins, we performed in silico simulations of FCF docking to all available crystal structures of septins. Docking of FCF with SEPT2 and SEPT3 indicated that FCF interacts preferentially with the nucleotide-binding pockets of septins. Strikingly, FCF is predicted to form hydrogen bonds with residues involved in GDP-binding, mimicking nucleotide binding. FCF docking with the structure of SEPT2-GppNHp, a nonhydrolyzable GTP analog, and SEPT7 showed that FCF may assume two alternative non-overlapping conformations deeply into and on the outer side of the nucleotide-binding pocket. Surprisingly, FCF was predicted to interact with the P-loop Walker A motif GxxxxGKS/T, which binds the phosphates of GTP, and the GTP specificity motif AKAD, which interacts with the guanine base of GTP, and highly conserved amino acids including a threonine, which is critical for GTP hydrolysis. Thus, in silico FCF exhibits a conserved mechanism of binding, interacting with septin signature motifs and residues involved in GTP binding and hydrolysis. Taken together, our results suggest that FCF stabilizes septins by locking them into a conformation that mimics a nucleotide-bound state, preventing further GTP binding and hydrolysis. Overall, this study provides the first insight into how FCF may bind and stabilize septins, and offers a blueprint for the rational design of FCF derivatives that could target septins with higher affinity and specificity.
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spelling doaj-art-1786c20f72384357b0601f2d6a29ceda2025-08-20T03:01:22ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-0195e9639010.1371/journal.pone.0096390In silico docking of forchlorfenuron (FCF) to septins suggests that FCF interferes with GTP binding.Dimitrios AngelisEva Pauline KarasmanisXiaobo BaiElias T SpiliotisSeptins are GTP-binding proteins that form cytoskeleton-like filaments, which are essential for many functions in eukaryotic organisms. Small molecule compounds that disrupt septin filament assembly are valuable tools for dissecting septin functions with high temporal control. To date, forchlorfenuron (FCF) is the only compound known to affect septin assembly and functions. FCF dampens the dynamics of septin assembly inducing the formation of enlarged stable polymers, but the underlying mechanism of action is unknown. To investigate how FCF binds and affects septins, we performed in silico simulations of FCF docking to all available crystal structures of septins. Docking of FCF with SEPT2 and SEPT3 indicated that FCF interacts preferentially with the nucleotide-binding pockets of septins. Strikingly, FCF is predicted to form hydrogen bonds with residues involved in GDP-binding, mimicking nucleotide binding. FCF docking with the structure of SEPT2-GppNHp, a nonhydrolyzable GTP analog, and SEPT7 showed that FCF may assume two alternative non-overlapping conformations deeply into and on the outer side of the nucleotide-binding pocket. Surprisingly, FCF was predicted to interact with the P-loop Walker A motif GxxxxGKS/T, which binds the phosphates of GTP, and the GTP specificity motif AKAD, which interacts with the guanine base of GTP, and highly conserved amino acids including a threonine, which is critical for GTP hydrolysis. Thus, in silico FCF exhibits a conserved mechanism of binding, interacting with septin signature motifs and residues involved in GTP binding and hydrolysis. Taken together, our results suggest that FCF stabilizes septins by locking them into a conformation that mimics a nucleotide-bound state, preventing further GTP binding and hydrolysis. Overall, this study provides the first insight into how FCF may bind and stabilize septins, and offers a blueprint for the rational design of FCF derivatives that could target septins with higher affinity and specificity.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0096390&type=printable
spellingShingle Dimitrios Angelis
Eva Pauline Karasmanis
Xiaobo Bai
Elias T Spiliotis
In silico docking of forchlorfenuron (FCF) to septins suggests that FCF interferes with GTP binding.
PLoS ONE
title In silico docking of forchlorfenuron (FCF) to septins suggests that FCF interferes with GTP binding.
title_full In silico docking of forchlorfenuron (FCF) to septins suggests that FCF interferes with GTP binding.
title_fullStr In silico docking of forchlorfenuron (FCF) to septins suggests that FCF interferes with GTP binding.
title_full_unstemmed In silico docking of forchlorfenuron (FCF) to septins suggests that FCF interferes with GTP binding.
title_short In silico docking of forchlorfenuron (FCF) to septins suggests that FCF interferes with GTP binding.
title_sort in silico docking of forchlorfenuron fcf to septins suggests that fcf interferes with gtp binding
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0096390&type=printable
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AT xiaobobai insilicodockingofforchlorfenuronfcftoseptinssuggeststhatfcfinterfereswithgtpbinding
AT eliastspiliotis insilicodockingofforchlorfenuronfcftoseptinssuggeststhatfcfinterfereswithgtpbinding