Dental plaque is a complex multispecies biofilm, and is a direct precursor of periodontal disease. The virulence of periodontal pathogens, such as Porphyromonas gingivalis, is expressed in the context of this polymicrobial community. Previously, we reported an antagonistic relationship between Streptococcus cristatus and P. gingivalis, and identified arginine deiminase (ArcA) of S. cristatus as the signaling molecule to which P. gingivalis responds by repressing the expression and production of FimA protein. Here we demonstrate that direct interaction between P. gingivalis and S. cristatus is necessary for the cell-cell communication. Two surface proteins of P. gingivalis, PGN_0294 and PGN_0806, were found to interact with S. cristatus ArcA. Using a peptide array analysis, we identified several P. gingivalis-binding sites of ArcA, which led to the discovery of an 11-mer peptide with the native sequence of ArcA that repressed expression of fimbriae and of gingipains. These data indicate that a functional motif of ArcA is sufficient to selectively alter virulence gene expression in P. gingivalis, and PGN_0294 and PGN_0806 may serve as receptors for ArcA. Our findings provide a molecular basis for future rational design of agents that interfere with the initiation and formation of a P. gingivalis-induced pathogenic community.
Peptide array functionalization via the Ugi four-component reaction
Ridder, B.; Mattes, D. S.; Nesterov-Mueller, A.; Breitling, F.; Meier, M. A. R.
The Ugi four-component reaction was investigated as a tool for the functionalization of peptide arrays via post-synthetic side-chain modification, mimicking post-translational processes. Additionally, as a proof of concept for the synthesis of peptidomimetics on arrays, the integration of an Ugi unit into a growing peptide chain was demonstrated.
Immuuntolerantsi häirumine, mille üheks väljundiks on antikehade teke organismile omaste biomolekulide vastu, on oluline patogeneetiline mehhanism mitmete laialdaselt levinud haiguste puhul ja seetõttu on autoantikehade määramine kujunenud oluliseks diagnostiliseks vahendiks. Artiklis on käsitletud autoantikehade esinemise olulisust haiguste tekke ja kulu prognoosimisel. Kuigi sellekohane info on veel üsna napp, on selge, et organismi immuunstaatuse muutus eelneb aastaid haiguse ilmnemisele ning autoimmuunset komponenti sisaldava haiguse kulg ja prognoos on seotud patsiendil esinevate kindlate autoantikehadega. Sellest tulenevalt võime loota, et organismi immuunstaatuse uurimine, eriti aga autoantikehade spektri iseloomustamine, on tulevikus geneetilise info analüüsimise kõrval üks täppismeditsiini olulisemaid tööriistu.
Antibody repertoire profiling with mimotope arrays
Pashova, Shina; Schneider, Christoph; von Gunten, Stephan; Pashov, Anastas
Large-scale profiling and monitoring of antibody repertoires is possible through next generation sequencing (NGS), phage display libraries and microarrays. These methods can be combined in a pipeline, which ultimately maps the antibody reactivities onto defined arrays of structures – peptides or carbohydrates. The arrays can help analyze the individual specificities or can be used as complex patterns. In any case, the targets recognized should formally be considered mimotopes unless they are proven to be epitopes driving the antibody synthesis. Here, the advantages and disadvantages of the major profiling techniques as well as their current and future application in disease prediction and vaccination are discussed.
Single-Molecule Detection on a Protein-Array Assay Platform for the Exposure of a Tuberculosis Antigen
Arrays promise to advance biology through parallel screening for binding partners. We show the combinatorial in situ synthesis of 40,000 peptide spots per square centimeter on a microchip. Our variant Merrifield synthesis immobilizes activated amino acids as monomers within particles, which are successively attracted by electric fields generated on each pixel electrode of the chip. With all different amino acids addressed, particles are melted at once to initiate coupling. Repetitive coupling cycles should allow for the translation of whole proteomes into arrays of overlapping peptides that could be used for proteome research and antibody profiling.
