Structural investigation of vitamin K epoxide reductase domain-containing protein in <i>Leptospira</i> species: a potential target for the development of new leptospirosis treatments as an alternative to antibiotics

Leptospirosis is a worldwide zoonosis caused by the motile bacterium Leptospira. This disease can cause hemorrhagic symptoms, multi-visceral and renal failures, resulting in one million cases and approximately 60,000 deaths each year. The motility of Leptospira is highly involved in its virulence and is ensured by the presence of two flagella in the periplasm. Several proteins that require the formation of disulfide bridges are essential for flagellar function. In Leptospira, these redox reactions are catalysed by the vitamin K epoxide reductase domain-containing protein (VKORdcp). The aim of the present work was to study the conservation of VKORdcp among Leptospira species and its interactions with putative substrates and inhibitor. Our results evidenced the presence of ten amino acids specific to either pathogenic or saprophytic species. Furthermore, structural studies revealed a higher affinity of the enzyme for vitamin K1 quinone, compared to ubiquinone. Finally, characterisation of the binding of a potential inhibitor revealed the involvement of some VKORdcp amino acids that have not been present in the human enzyme, in particular the polar residue D114. Our study thus paves the way for the future development of Leptospira VKORdcp inhibitors, capable of blocking bacterial motility. Such molecules could therefore offer a promising therapeutic alternative to antibiotics, especially in the event of the emergence of antibiotic-resistant strains. Communicated by Ramaswamy H. Sarma</p

supplement information-tables.xlsx

Table 1 presents the raw data on rodent captured during 4 years. Their abundance is evaluated through the trapping success, which is based on the numbers by trapping night.<br><br>Table 2 presents the bait consumption in grammes per day (J1 to J31) during year 3. <br><br>Table 3 presents the bait consumption in grammes per day (J1 to J31) during year 4

Model 1 results.

<p>Adjusted odds ratios and 95% confidence intervals for pathogen occurrence in <i>R</i>. <i>norvegicus</i> from Chanteraines park calculated using the best-fitted general linear model identified using a stepwise backward selection on the Akaike Information Criterion.</p

Map of the Chanteraines park (light green: green areas, light blue: water areas).

<p>The map shows all trap locations (black dots), highlights location of traps where rats were caught (colored squares, triangles, and dots), specifies the VKORC1 genotype of the captured rats (orange square: <i>Y139F/Y139F</i>, yellow triangle: <i>Y139F/-</i>, blue dot: <i>-/-</i>) and presents results of the GeneClass analysis (flags: migrants).</p

Individual liver concentration (ng.g^-1) of the eight AVK compounds investigated, depending on <i>VKORC1</i> genotype.

<p>Individual liver concentration (ng.g^-1) of the eight AVK compounds investigated, depending on <i>VKORC1</i> genotype.</p

Pairwise relationship coefficients between female and male individuals (<i>r</i>) plotted against geographic separation (in meters, m) in Chanteraines rat population assessed using 13 microsatellite markers.

<p>The sample consisted of 49 males and 37 females; sample size at each distance is specified. Coefficient values significantly different from zero are shown with an asterisk.</p

Boxplot and scatterplot of the total AVK residue liver concentration (ng.g^-1) depending on the <i>VKORC1</i> genotype (log scale).

<p>Boxplot and scatterplot of the total AVK residue liver concentration (ng.g^-1) depending on the <i>VKORC1</i> genotype (log scale).</p

Summary of the parasites investigated and detected in the brown rat population from Chanteraines public park, France.

<p>Asterisks show potentially zoonotic parasites.</p

Characterization of the 13 microsatellite markers.

<p>Characterization of the 13 microsatellite markers.</p

Graphical representation of the structuring of the main parasites of the brown rats from Chanteraines using the network approach.

<p>The edge width is proportional to the number of individual hosts involved (numbers correspond to the number of rats sharing the parasites). The node size is proportional to the number of hosts infected (prevalence).</p