Project description:Type IV Pili (T4P) are dynamic surface appendages that mediate adherence, motility, and DNA uptake in Kingella kingae, an important pediatric pathogen that causes osteoarticular infections, bacteremia, and endocarditis. While the major pilin subunit in K. kingae T4P is well characterized, the contribution of minor pilins to T4P structure and function remains unknown. Here, we used proteomics, molecular genetics, biochemical analyses, and structural modeling to identify and characterize all eight minor pilins in K. kingae. We identified a conserved operon of core minor pilin genes encoding FimT, PilV, PilW, PilX, and PilE that promotes surface piliation, adherence to epithelial cells, twitching motility, and natural transformation. Deletion of the fimTpilVWXE locus phenocopied loss of the PilC1 and PilC2 adhesins, and AlphaFold modeling combined with bacterial two-hybrid analysis suggested that FimT, PilV, PilW, and PilX form a complex at the pilus tip. The PilA2, ComP, and KK03_01180 minor pilins were dispensable for adherence and motility but promoted natural transformation and formed protein-protein interactions with the major pilin, suggesting that these proteins are incorporated throughout the pilus shaft. These findings support a new model for the architecture of the K. kingae type IV pilus, with distinct minor pilins localizing to different sites on the pilus fiber and mediating specialized functions essential for virulence.
Project description:Kingella negevensis is a newly described gram-negative bacterium in the Neisseriaceae family and is closely related to Kingella kingae, an important cause of pediatric osteoarticular infections and other invasive diseases. Like K. kingae, K. negevensis can be isolated from the oropharynx of young children, although at a much lower rate. Due to the potential for misidentification as K. kingae, the burden of disease due to K. negevensis is currently unknown. Similarly, there is little known about virulence factors present in K. negevensis and how they compare to virulence factors in K. kingae. Using a variety of approaches, we show that K. negevensis produces many of the same putative virulence factors that are present in K. kingae, including a polysaccharide capsule, a secreted exopolysaccharide, a Knh-like trimeric autotransporter, and type IV pili, suggesting that K. negevensis may have significant pathogenic potential.
Project description:Kingella kingae is a betaproteobacterium from the order Neisseriales, and it is an agent of invasive infections in children. We sequenced the genome from the septic arthritis strain 11220434. It is composed of a 1,990,794-bp chromosome but no plasmid, and it contains 2,042 protein-coding genes and 52 RNA genes, including 3 rRNA genes.
