Investigations on the substrate binding sites of hemolysin B, an ABC transporter, of a type 1 secretion system

The ABC transporter hemolysin B (HlyB) is the key protein of the HlyA secretion system, a paradigm of type 1 secretion systems (T1SS). T1SS catalyze the one-step substrate transport across both membranes of Gram-negative bacteria. The HlyA T1SS is composed of the ABC transporter (HlyB), the membrane...

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Main Authors: Zohreh Pourhassan N., Eymen Hachani, Olivia Spitz, Sander H. J. Smits, Lutz Schmitt
Format: Article
Language:English
Published: Frontiers Media S.A. 2022-12-01
Series:Frontiers in Microbiology
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fmicb.2022.1055032/full
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author Zohreh Pourhassan N.
Eymen Hachani
Olivia Spitz
Sander H. J. Smits
Sander H. J. Smits
Lutz Schmitt
author_facet Zohreh Pourhassan N.
Eymen Hachani
Olivia Spitz
Sander H. J. Smits
Sander H. J. Smits
Lutz Schmitt
author_sort Zohreh Pourhassan N.
collection DOAJ
description The ABC transporter hemolysin B (HlyB) is the key protein of the HlyA secretion system, a paradigm of type 1 secretion systems (T1SS). T1SS catalyze the one-step substrate transport across both membranes of Gram-negative bacteria. The HlyA T1SS is composed of the ABC transporter (HlyB), the membrane fusion protein (HlyD), and the outer membrane protein TolC. HlyA is a member of the RTX (repeats in toxins) family harboring GG repeats that bind Ca2+ in the C-terminus upstream of the secretion signal. Beside the GG repeats, the presence of an amphipathic helix (AH) in the C-terminus of HlyA is essential for secretion. Here, we propose that a consensus length between the GG repeats and the AH affects the secretion efficiency of the heterologous RTX secreted by the HlyA T1SS. Our in silico studies along with mutagenesis and biochemical analysis demonstrate that there are two binding pockets in the nucleotide binding domain of HlyB for HlyA. The distances between the domains of HlyB implied to interact with HlyA indicated that simultaneous binding of the substrate to both cytosolic domains of HlyB, the NBD and CLD, is possible and required for efficient substrate secretion.
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spelling doaj.art-f6a089f934d645288f2198cd5e385bcb2022-12-22T04:35:53ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2022-12-011310.3389/fmicb.2022.10550321055032Investigations on the substrate binding sites of hemolysin B, an ABC transporter, of a type 1 secretion systemZohreh Pourhassan N.0Eymen Hachani1Olivia Spitz2Sander H. J. Smits3Sander H. J. Smits4Lutz Schmitt5Institute of Biochemistry, Heinrich Heine University, Düsseldorf, GermanyInstitute of Biochemistry, Heinrich Heine University, Düsseldorf, GermanyInstitute of Biochemistry, Heinrich Heine University, Düsseldorf, GermanyInstitute of Biochemistry, Heinrich Heine University, Düsseldorf, GermanyCenter for Structural Studies, Heinrich Heine University, Düsseldorf, GermanyInstitute of Biochemistry, Heinrich Heine University, Düsseldorf, GermanyThe ABC transporter hemolysin B (HlyB) is the key protein of the HlyA secretion system, a paradigm of type 1 secretion systems (T1SS). T1SS catalyze the one-step substrate transport across both membranes of Gram-negative bacteria. The HlyA T1SS is composed of the ABC transporter (HlyB), the membrane fusion protein (HlyD), and the outer membrane protein TolC. HlyA is a member of the RTX (repeats in toxins) family harboring GG repeats that bind Ca2+ in the C-terminus upstream of the secretion signal. Beside the GG repeats, the presence of an amphipathic helix (AH) in the C-terminus of HlyA is essential for secretion. Here, we propose that a consensus length between the GG repeats and the AH affects the secretion efficiency of the heterologous RTX secreted by the HlyA T1SS. Our in silico studies along with mutagenesis and biochemical analysis demonstrate that there are two binding pockets in the nucleotide binding domain of HlyB for HlyA. The distances between the domains of HlyB implied to interact with HlyA indicated that simultaneous binding of the substrate to both cytosolic domains of HlyB, the NBD and CLD, is possible and required for efficient substrate secretion.https://www.frontiersin.org/articles/10.3389/fmicb.2022.1055032/fullABC transporterprotein secretionputative binding pocketssubstrate interactionbacterial secretion systems
spellingShingle Zohreh Pourhassan N.
Eymen Hachani
Olivia Spitz
Sander H. J. Smits
Sander H. J. Smits
Lutz Schmitt
Investigations on the substrate binding sites of hemolysin B, an ABC transporter, of a type 1 secretion system
Frontiers in Microbiology
ABC transporter
protein secretion
putative binding pockets
substrate interaction
bacterial secretion systems
title Investigations on the substrate binding sites of hemolysin B, an ABC transporter, of a type 1 secretion system
title_full Investigations on the substrate binding sites of hemolysin B, an ABC transporter, of a type 1 secretion system
title_fullStr Investigations on the substrate binding sites of hemolysin B, an ABC transporter, of a type 1 secretion system
title_full_unstemmed Investigations on the substrate binding sites of hemolysin B, an ABC transporter, of a type 1 secretion system
title_short Investigations on the substrate binding sites of hemolysin B, an ABC transporter, of a type 1 secretion system
title_sort investigations on the substrate binding sites of hemolysin b an abc transporter of a type 1 secretion system
topic ABC transporter
protein secretion
putative binding pockets
substrate interaction
bacterial secretion systems
url https://www.frontiersin.org/articles/10.3389/fmicb.2022.1055032/full
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