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Virulence regulation with Venus flytrap domains: structure and function of the periplasmic moiety of the sensor-kinase BvgS.

Dupré E, Herrou J, Lensink MF, Wintjens R, Vagin A, Lebedev A, Crosson S, Villeret V, Locht C, Antoine R, Jacob-Dubuisson F - PLoS Pathog. (2015)

Bottom Line: Signaling the presence of negative signals perceived by the periplasmic domains implies a shift of BvgS to a distinct state of conformation and activity, corresponding to the avirulent phase.The response to negative modulation depends on the integrity of the periplasmic dimer, indicating that the shift to the kinase-off state implies a concerted conformational transition.This work lays the bases to understand virulence regulation in Bordetella.

View Article: PubMed Central - PubMed

Affiliation: Center for Infection and Immunity (CIIL), Institut Pasteur de Lille, Lille, France; Center for Infection and Immunity (CIIL), University Lille North of France, Lille, France; UMR 8204, Centre National de la Recherche Scientifique (CNRS), Lille, France; U1019, Institut National de la Santé et de la Recherche Médicale (INSERM), Lille, France.

ABSTRACT
Two-component systems (TCS) represent major signal-transduction pathways for adaptation to environmental conditions, and regulate many aspects of bacterial physiology. In the whooping cough agent Bordetella pertussis, the TCS BvgAS controls the virulence regulon, and is therefore critical for pathogenicity. BvgS is a prototypical TCS sensor-kinase with tandem periplasmic Venus flytrap (VFT) domains. VFT are bi-lobed domains that typically close around specific ligands using clamshell motions. We report the X-ray structure of the periplasmic moiety of BvgS, an intricate homodimer with a novel architecture. By combining site-directed mutagenesis, functional analyses and molecular modeling, we show that the conformation of the periplasmic moiety determines the state of BvgS activity. The intertwined structure of the periplasmic portion and the different conformation and dynamics of its mobile, membrane-distal VFT1 domains, and closed, membrane-proximal VFT2 domains, exert a conformational strain onto the transmembrane helices, which sets the cytoplasmic moiety in a kinase-on state by default corresponding to the virulent phase of the bacterium. Signaling the presence of negative signals perceived by the periplasmic domains implies a shift of BvgS to a distinct state of conformation and activity, corresponding to the avirulent phase. The response to negative modulation depends on the integrity of the periplasmic dimer, indicating that the shift to the kinase-off state implies a concerted conformational transition. This work lays the bases to understand virulence regulation in Bordetella. As homologous sensor-kinases control virulence features of diverse bacterial pathogens, the BvgS structure and mechanism may pave the way for new modes of targeted therapeutic interventions.

No MeSH data available.


Related in: MedlinePlus

Interfaces between the VFT domains important for the kinase-on state.A. Surface representation of protomer B (in blue); the residues interacting with protomer A are shown in orange. To help visualizing these interactions, a “ghost” protomer A is represented in transparent white on top of protomer B. B. Illustration of the VFT1-VFT2 inter-protomer interface. A side view of BvgS is shown in surface representation, with the VFT1 of one protomer in green and the VFT2 of the other protomer in pale blue. A zoom delimited by a dashed orange box shows specific residues that are critical for BvgS function, as shown by mutagenesis. The side chains of Tyr81 and Glu86 of the β hairpin in VFT1L1 form hydrogen bonds with Phe386 and Arg388 at one extremity of the VFT2 hinge, and with residues of the α helix H17. Glu200 belongs to VFT1L2, and its side chain makes hydrogen bonds with Asn393 and Gly394 at the other extremity of the VFT2 hinge. C. Illustration of the VFT2-Ct domain inter-protomer interface. In the upper panel, BvgS is shown in surface representation, with protomer A in green and protomer B in blue. A zoom shows specific residues involved in critical interactions for BvgS kinase activity. Thus, Trp535 from H19 stacks in a hydrophobic and aromatic pocket mainly lined with VFT2L2 residues of the other protomer, and Arg472 and Tyr473 from helix H16 in VFT2L2 interact with Ser528 and Asp531 in the Ct loop of the other protomer. Hydrogen-bond distances are reported in angstroms.
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ppat.1004700.g004: Interfaces between the VFT domains important for the kinase-on state.A. Surface representation of protomer B (in blue); the residues interacting with protomer A are shown in orange. To help visualizing these interactions, a “ghost” protomer A is represented in transparent white on top of protomer B. B. Illustration of the VFT1-VFT2 inter-protomer interface. A side view of BvgS is shown in surface representation, with the VFT1 of one protomer in green and the VFT2 of the other protomer in pale blue. A zoom delimited by a dashed orange box shows specific residues that are critical for BvgS function, as shown by mutagenesis. The side chains of Tyr81 and Glu86 of the β hairpin in VFT1L1 form hydrogen bonds with Phe386 and Arg388 at one extremity of the VFT2 hinge, and with residues of the α helix H17. Glu200 belongs to VFT1L2, and its side chain makes hydrogen bonds with Asn393 and Gly394 at the other extremity of the VFT2 hinge. C. Illustration of the VFT2-Ct domain inter-protomer interface. In the upper panel, BvgS is shown in surface representation, with protomer A in green and protomer B in blue. A zoom shows specific residues involved in critical interactions for BvgS kinase activity. Thus, Trp535 from H19 stacks in a hydrophobic and aromatic pocket mainly lined with VFT2L2 residues of the other protomer, and Arg472 and Tyr473 from helix H16 in VFT2L2 interact with Ser528 and Asp531 in the Ct loop of the other protomer. Hydrogen-bond distances are reported in angstroms.

Mentions: The VFT1L1s interact with each other through several hydrogen bonds between their H8s, while the VFT2s are not directly interconnected. Both lobes of the VFT1s, VFT1L1 and VFT1L2, contact the hinge and lobes of VFT2 of the opposite protomer (Fig. 4), forming the largest dimeric interfaces. Other large interfaces occur between VFT1L2 and VFT2 of the same protomer, and between VFT2L2 and the Ct domains. In particular, both the Ct loop and the N terminus of H19 strongly interact with VFT2L2 of the opposite protomer through hydrogen bonds and through π-stacking interactions that involve a conserved residue in the BvgS family, Trp535 (Fig. 4).


Virulence regulation with Venus flytrap domains: structure and function of the periplasmic moiety of the sensor-kinase BvgS.

Dupré E, Herrou J, Lensink MF, Wintjens R, Vagin A, Lebedev A, Crosson S, Villeret V, Locht C, Antoine R, Jacob-Dubuisson F - PLoS Pathog. (2015)

Interfaces between the VFT domains important for the kinase-on state.A. Surface representation of protomer B (in blue); the residues interacting with protomer A are shown in orange. To help visualizing these interactions, a “ghost” protomer A is represented in transparent white on top of protomer B. B. Illustration of the VFT1-VFT2 inter-protomer interface. A side view of BvgS is shown in surface representation, with the VFT1 of one protomer in green and the VFT2 of the other protomer in pale blue. A zoom delimited by a dashed orange box shows specific residues that are critical for BvgS function, as shown by mutagenesis. The side chains of Tyr81 and Glu86 of the β hairpin in VFT1L1 form hydrogen bonds with Phe386 and Arg388 at one extremity of the VFT2 hinge, and with residues of the α helix H17. Glu200 belongs to VFT1L2, and its side chain makes hydrogen bonds with Asn393 and Gly394 at the other extremity of the VFT2 hinge. C. Illustration of the VFT2-Ct domain inter-protomer interface. In the upper panel, BvgS is shown in surface representation, with protomer A in green and protomer B in blue. A zoom shows specific residues involved in critical interactions for BvgS kinase activity. Thus, Trp535 from H19 stacks in a hydrophobic and aromatic pocket mainly lined with VFT2L2 residues of the other protomer, and Arg472 and Tyr473 from helix H16 in VFT2L2 interact with Ser528 and Asp531 in the Ct loop of the other protomer. Hydrogen-bond distances are reported in angstroms.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4352136&req=5

ppat.1004700.g004: Interfaces between the VFT domains important for the kinase-on state.A. Surface representation of protomer B (in blue); the residues interacting with protomer A are shown in orange. To help visualizing these interactions, a “ghost” protomer A is represented in transparent white on top of protomer B. B. Illustration of the VFT1-VFT2 inter-protomer interface. A side view of BvgS is shown in surface representation, with the VFT1 of one protomer in green and the VFT2 of the other protomer in pale blue. A zoom delimited by a dashed orange box shows specific residues that are critical for BvgS function, as shown by mutagenesis. The side chains of Tyr81 and Glu86 of the β hairpin in VFT1L1 form hydrogen bonds with Phe386 and Arg388 at one extremity of the VFT2 hinge, and with residues of the α helix H17. Glu200 belongs to VFT1L2, and its side chain makes hydrogen bonds with Asn393 and Gly394 at the other extremity of the VFT2 hinge. C. Illustration of the VFT2-Ct domain inter-protomer interface. In the upper panel, BvgS is shown in surface representation, with protomer A in green and protomer B in blue. A zoom shows specific residues involved in critical interactions for BvgS kinase activity. Thus, Trp535 from H19 stacks in a hydrophobic and aromatic pocket mainly lined with VFT2L2 residues of the other protomer, and Arg472 and Tyr473 from helix H16 in VFT2L2 interact with Ser528 and Asp531 in the Ct loop of the other protomer. Hydrogen-bond distances are reported in angstroms.
Mentions: The VFT1L1s interact with each other through several hydrogen bonds between their H8s, while the VFT2s are not directly interconnected. Both lobes of the VFT1s, VFT1L1 and VFT1L2, contact the hinge and lobes of VFT2 of the opposite protomer (Fig. 4), forming the largest dimeric interfaces. Other large interfaces occur between VFT1L2 and VFT2 of the same protomer, and between VFT2L2 and the Ct domains. In particular, both the Ct loop and the N terminus of H19 strongly interact with VFT2L2 of the opposite protomer through hydrogen bonds and through π-stacking interactions that involve a conserved residue in the BvgS family, Trp535 (Fig. 4).

Bottom Line: Signaling the presence of negative signals perceived by the periplasmic domains implies a shift of BvgS to a distinct state of conformation and activity, corresponding to the avirulent phase.The response to negative modulation depends on the integrity of the periplasmic dimer, indicating that the shift to the kinase-off state implies a concerted conformational transition.This work lays the bases to understand virulence regulation in Bordetella.

View Article: PubMed Central - PubMed

Affiliation: Center for Infection and Immunity (CIIL), Institut Pasteur de Lille, Lille, France; Center for Infection and Immunity (CIIL), University Lille North of France, Lille, France; UMR 8204, Centre National de la Recherche Scientifique (CNRS), Lille, France; U1019, Institut National de la Santé et de la Recherche Médicale (INSERM), Lille, France.

ABSTRACT
Two-component systems (TCS) represent major signal-transduction pathways for adaptation to environmental conditions, and regulate many aspects of bacterial physiology. In the whooping cough agent Bordetella pertussis, the TCS BvgAS controls the virulence regulon, and is therefore critical for pathogenicity. BvgS is a prototypical TCS sensor-kinase with tandem periplasmic Venus flytrap (VFT) domains. VFT are bi-lobed domains that typically close around specific ligands using clamshell motions. We report the X-ray structure of the periplasmic moiety of BvgS, an intricate homodimer with a novel architecture. By combining site-directed mutagenesis, functional analyses and molecular modeling, we show that the conformation of the periplasmic moiety determines the state of BvgS activity. The intertwined structure of the periplasmic portion and the different conformation and dynamics of its mobile, membrane-distal VFT1 domains, and closed, membrane-proximal VFT2 domains, exert a conformational strain onto the transmembrane helices, which sets the cytoplasmic moiety in a kinase-on state by default corresponding to the virulent phase of the bacterium. Signaling the presence of negative signals perceived by the periplasmic domains implies a shift of BvgS to a distinct state of conformation and activity, corresponding to the avirulent phase. The response to negative modulation depends on the integrity of the periplasmic dimer, indicating that the shift to the kinase-off state implies a concerted conformational transition. This work lays the bases to understand virulence regulation in Bordetella. As homologous sensor-kinases control virulence features of diverse bacterial pathogens, the BvgS structure and mechanism may pave the way for new modes of targeted therapeutic interventions.

No MeSH data available.


Related in: MedlinePlus