Year: 2013
Type: article
Abstract: Gingipain activity in Porphyromonas gingivalis, the major etiological agent in adult periodontitis, is post-translationally regulated by unique Vim proteins including VimF, a putative glycosyltransferase. To ascertain the VimF mediated phenotype we first inactivated the vimF gene in P. gingivalis ATCC 33277 (FLL476), a less virulent fimbriated strain. We observed that the vimF-defective mutant (FLL476) showed a phenotype similar to that of the vimF-defective mutant (FLL95) in the P. gingivalis W83 background. While hemagglutination was not detected and autoaggregationn was reduced, biofilm formation was increased in FLL476. Also, invasive capacity decreased for this mutant. Furthermore, fimbrial structures were missing in FLL476, suggesting the role of VimF in fimbrial processing. We were able to restore the wildtype phenotype by complementing the defect. Secondly, we cloned, expressed and purified the vimF gene and demonstrated its ability to glycosylate gingipains. In vitro glycosyltransferase activity for rVimF was observed using UDP-galactose and N-acetylglucosamine as donor and acceptor substrates, respectively. Further, in the presence of rVimF and UDP-galactose, a 60 kDa protein from the extracellular fraction of FLL95 which was identified my mass spectrometry as Rgp gingipain, immunoreacted with the glycan specific mAb IB5 antibody. Finally, the polyclonal antibody raised against rVimF that did not react well with native VimF from P. gingilvalis, reacted with a 47 kDa protein when the fractions were first deglycosylated before probing with the antibody. Galactose is vital for growing glycan chain leading to maturation/activation of gingipains. Taken together, these results suggest that VimF glycoprotein is a galactosyltransferase that may be specific for gingipain glycosylation.
Author: Arun Muthiah
Language: English
Subfield: Periodontics
Field: Dentistry
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2182456035