An Intermolecular π-Stacking Interaction Drives Conformational Changes Necessary to β-Barrel Formation in a Pore-Forming Toxin

ABSTRACT The crystal structures of the soluble monomers of the pore-forming cholesterol-dependent cytolysins (CDCs) contain two α-helical bundles that flank a twisted core β-sheet. This protein fold is the hallmark of the CDCs, as well as of the membrane attack complex/perforin immune defense protei...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Joshua R. Burns, Craig J. Morton, Michael W. Parker, Rodney K. Tweten
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2019
Materias:	β-barrel cholesterol-dependent cytolysin membrane attack complex oligomer perforin Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/70c7a6f486474d4393e2f0732710f0ed
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:70c7a6f486474d4393e2f0732710f0ed
record_format	dspace
spelling	oai:doaj.org-article:70c7a6f486474d4393e2f0732710f0ed2021-11-15T16:22:09ZAn Intermolecular π-Stacking Interaction Drives Conformational Changes Necessary to β-Barrel Formation in a Pore-Forming Toxin10.1128/mBio.01017-192150-7511https://doaj.org/article/70c7a6f486474d4393e2f0732710f0ed2019-08-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.01017-19https://doaj.org/toc/2150-7511ABSTRACT The crystal structures of the soluble monomers of the pore-forming cholesterol-dependent cytolysins (CDCs) contain two α-helical bundles that flank a twisted core β-sheet. This protein fold is the hallmark of the CDCs, as well as of the membrane attack complex/perforin immune defense proteins and the stonefish toxins. To form the β-barrel pore, a core β-sheet is flattened to align the membrane-spanning β-hairpins. Concomitantly with this conformational change, the two α-helical bundles that flank the core β-sheet break their restraining contacts and refold into two membrane-spanning β-hairpins of the β-barrel pore. The studies herein show that in the monomer structure of the archetype CDC perfringolysin O (PFO), a conserved Met-Met-Phe triad simultaneously contributes to maintaining the twist in this core β-sheet, as well as restricting the α-helical–to–β-strand transition necessary to form one of two membrane-spanning β-hairpins. A previously identified intermolecular π-stacking interaction is now shown to disrupt the interactions mediated by this conserved triad. This is required to establish the subsequent intermolecular electrostatic interaction, which has previously been shown to drive the final conformational changes necessary to form the β-barrel pore. Hence, these studies show that the intermolecular π-stacking and electrostatic interactions work in tandem to flatten the core β-sheet and initiate the α-helical–to–β-strand transitions to form the β-barrel pore. IMPORTANCE A unique feature of the CDC/MACPF/SNTX (cholesterol-dependent cytolysin/membrane attack complex perforin/stonefish toxin) superfamily of pore-forming toxins is that the β-strands that comprise the β-barrel pore are derived from a pair of α-helical bundles. These studies reveal the molecular basis by which the formation of intermolecular interactions within the prepore complex drive the disruption of intramolecular interactions within each monomer of the prepore to trigger the α-helical–to–β-strand transition and formation of the β-barrel pore.Joshua R. BurnsCraig J. MortonMichael W. ParkerRodney K. TwetenAmerican Society for Microbiologyarticleβ-barrelcholesterol-dependent cytolysinmembrane attack complexoligomerperforinMicrobiologyQR1-502ENmBio, Vol 10, Iss 4 (2019)
institution	DOAJ
collection	DOAJ
language	EN
topic	β-barrel cholesterol-dependent cytolysin membrane attack complex oligomer perforin Microbiology QR1-502
spellingShingle	β-barrel cholesterol-dependent cytolysin membrane attack complex oligomer perforin Microbiology QR1-502 Joshua R. Burns Craig J. Morton Michael W. Parker Rodney K. Tweten An Intermolecular π-Stacking Interaction Drives Conformational Changes Necessary to β-Barrel Formation in a Pore-Forming Toxin
description	ABSTRACT The crystal structures of the soluble monomers of the pore-forming cholesterol-dependent cytolysins (CDCs) contain two α-helical bundles that flank a twisted core β-sheet. This protein fold is the hallmark of the CDCs, as well as of the membrane attack complex/perforin immune defense proteins and the stonefish toxins. To form the β-barrel pore, a core β-sheet is flattened to align the membrane-spanning β-hairpins. Concomitantly with this conformational change, the two α-helical bundles that flank the core β-sheet break their restraining contacts and refold into two membrane-spanning β-hairpins of the β-barrel pore. The studies herein show that in the monomer structure of the archetype CDC perfringolysin O (PFO), a conserved Met-Met-Phe triad simultaneously contributes to maintaining the twist in this core β-sheet, as well as restricting the α-helical–to–β-strand transition necessary to form one of two membrane-spanning β-hairpins. A previously identified intermolecular π-stacking interaction is now shown to disrupt the interactions mediated by this conserved triad. This is required to establish the subsequent intermolecular electrostatic interaction, which has previously been shown to drive the final conformational changes necessary to form the β-barrel pore. Hence, these studies show that the intermolecular π-stacking and electrostatic interactions work in tandem to flatten the core β-sheet and initiate the α-helical–to–β-strand transitions to form the β-barrel pore. IMPORTANCE A unique feature of the CDC/MACPF/SNTX (cholesterol-dependent cytolysin/membrane attack complex perforin/stonefish toxin) superfamily of pore-forming toxins is that the β-strands that comprise the β-barrel pore are derived from a pair of α-helical bundles. These studies reveal the molecular basis by which the formation of intermolecular interactions within the prepore complex drive the disruption of intramolecular interactions within each monomer of the prepore to trigger the α-helical–to–β-strand transition and formation of the β-barrel pore.
format	article
author	Joshua R. Burns Craig J. Morton Michael W. Parker Rodney K. Tweten
author_facet	Joshua R. Burns Craig J. Morton Michael W. Parker Rodney K. Tweten
author_sort	Joshua R. Burns
title	An Intermolecular π-Stacking Interaction Drives Conformational Changes Necessary to β-Barrel Formation in a Pore-Forming Toxin
title_short	An Intermolecular π-Stacking Interaction Drives Conformational Changes Necessary to β-Barrel Formation in a Pore-Forming Toxin
title_full	An Intermolecular π-Stacking Interaction Drives Conformational Changes Necessary to β-Barrel Formation in a Pore-Forming Toxin
title_fullStr	An Intermolecular π-Stacking Interaction Drives Conformational Changes Necessary to β-Barrel Formation in a Pore-Forming Toxin
title_full_unstemmed	An Intermolecular π-Stacking Interaction Drives Conformational Changes Necessary to β-Barrel Formation in a Pore-Forming Toxin
title_sort	intermolecular π-stacking interaction drives conformational changes necessary to β-barrel formation in a pore-forming toxin
publisher	American Society for Microbiology
publishDate	2019
url	https://doaj.org/article/70c7a6f486474d4393e2f0732710f0ed
work_keys_str_mv	AT joshuarburns anintermolecularpstackinginteractiondrivesconformationalchangesnecessarytobbarrelformationinaporeformingtoxin AT craigjmorton anintermolecularpstackinginteractiondrivesconformationalchangesnecessarytobbarrelformationinaporeformingtoxin AT michaelwparker anintermolecularpstackinginteractiondrivesconformationalchangesnecessarytobbarrelformationinaporeformingtoxin AT rodneyktweten anintermolecularpstackinginteractiondrivesconformationalchangesnecessarytobbarrelformationinaporeformingtoxin AT joshuarburns intermolecularpstackinginteractiondrivesconformationalchangesnecessarytobbarrelformationinaporeformingtoxin AT craigjmorton intermolecularpstackinginteractiondrivesconformationalchangesnecessarytobbarrelformationinaporeformingtoxin AT michaelwparker intermolecularpstackinginteractiondrivesconformationalchangesnecessarytobbarrelformationinaporeformingtoxin AT rodneyktweten intermolecularpstackinginteractiondrivesconformationalchangesnecessarytobbarrelformationinaporeformingtoxin
_version_	1718426907686469632

An Intermolecular π-Stacking Interaction Drives Conformational Changes Necessary to β-Barrel Formation in a Pore-Forming Toxin

Ejemplares similares