| 1. |
- Breidenstein, Annika, et al.
(författare)
-
PrgE: an OB-fold protein from plasmid pCF10 with striking differences to prototypical bacterial SSBs
- 2024
-
Ingår i: Life Science Alliance. - : Life Science Alliance. - 2575-1077. ; 7:8
-
Tidskriftsartikel (refereegranskat)abstract
- A major pathway for horizontal gene transfer is the transmission of DNA from donor to recipient cells via plasmid-encoded type IV secretion systems (T4SSs). Many conjugative plasmids encode for a single-stranded DNA-binding protein (SSB) together with their T4SS. Some of these SSBs have been suggested to aid in establishing the plasmid in the recipient cell, but for many, their function remains unclear. Here, we characterize PrgE, a proposed SSB from the Enterococcus faecalis plasmid pCF10. We show that PrgE is not essential for conjugation. Structurally, it has the characteristic OB-fold of SSBs, but it has very unusual DNA-binding properties. Our DNA-bound structure shows that PrgE binds ssDNA like beads on a string supported by its N-terminal tail. In vitro studies highlight the plasticity of PrgE oligomerization and confirm the importance of the N-terminus. Unlike other SSBs, PrgE binds both double- and single-stranded DNA equally well. This shows that PrgE has a quaternary assembly and DNA-binding properties that are very different from the prototypical bacterial SSB, but also different from eukaryotic SSBs.
|
|
| 2. |
- Jäger, Franziska, et al.
(författare)
-
Structure of the enterococcal T4SS protein PrgL reveals unique dimerization interface in the VirB8 protein family
- 2022
-
Ingår i: Structure. - : Elsevier BV. - 0969-2126 .- 1878-4186. ; 30:6, s. 876-885.e5
-
Tidskriftsartikel (refereegranskat)abstract
- Multidrug-resistant bacteria pose serious problems in hospital-acquired infections (HAIs). Most antibiotic resistance genes are acquired via conjugative gene transfer, mediated by type 4 secretion systems (T4SS). Although most multidrug-resistant bacteria responsible for HAIs are of Gram-positive origin, with enterococci being major contributors, mostly Gram-negative T4SSs have been characterized. Here, we describe the structure and organization of PrgL, a core protein of the T4SS channel, encoded by the pCF10 plasmid from Enterococcus faecalis. The structure of PrgL displays similarity to VirB8 proteins of Gram-negative T4SSs. In vitro experiments show that the soluble domain alone is enough to drive both dimerization and dodecamerization, with a dimerization interface that differs from all other known VirB8-like proteins. In vivo experiments verify the importance of PrgL dimerization. Our findings provide insight into the molecular building blocks of Gram-positive T4SS, highlighting similarities but also unique features in PrgL compared to other VirB8-like proteins.
|
|
| 3. |
- Lamy, Anaïs, et al.
(författare)
-
ATP2, The essential P4-ATPase of malaria parasites, catalyzes lipid-stimulated ATP hydrolysis in complex with a Cdc50 β-subunit
- 2021
-
Ingår i: Emerging Microbes & Infections. - : Taylor & Francis. - 2222-1751. ; 10:1, s. 132-147
-
Tidskriftsartikel (refereegranskat)abstract
- Gene targeting approaches have demonstrated the essential role for the malaria parasite of membrane transport proteins involved in lipid transport and in the maintenance of membrane lipid asymmetry, representing emerging oportunites for therapeutical intervention. This is the case of ATP2, a Plasmodium-encoded 4 P-type ATPase (P4-ATPase or lipid flippase), whose activity is completely irreplaceable during the asexual stages of the parasite. Moreover, a recent chemogenomic study has situated ATP2 as the possible target of two antimalarial drug candidates. In eukaryotes, P4-ATPases assure the asymmetric phospholipid distribution in membranes by translocating phospholipids from the outer to the inner leaflet. In this work, we have used a recombinantly-produced P. chabaudi ATP2 (PcATP2), to gain insights into the function and structural organization of this essential transporter. Our work demonstrates that PcATP2 associates with two of the three Plasmodium-encoded Cdc50 proteins: PcCdc50B and PcCdc50A. Purified PcATP2/PcCdc50B complex displays ATPase activity in the presence of either phosphatidylserine or phosphatidylethanolamine. In addition, this activity is upregulated by phosphatidylinositol 4-phosphate. Overall, our work describes the first biochemical characterization of a Plasmodium lipid flippase, a first step towards the understanding of the essential physiological role of this transporter and towards its validation as a potential antimalarial drug target.
|
|
