FIG. 8.

Proposed maturation pathways leading to the generation of five differentially modified enzymes from rgpA and rgpB of P. gingivalis. HRgpA, RgpA, and mt-RgpA are all products of rgpA. The catalytic chain of the monomeric enzymes may be derived either from the translation product of the full-length rgpA transcript or via translation of a truncated transcript. Variable levels of glycan addition then leads to the formation of either RgpA or mt-RgpA. RgpB and mt-RgpB are derived from translation of an rgpB transcript. RgpB may acquire different carbohydrate modifications compared to RgpA. mt-RgpB is glycosylated to a similar extent as mt-RgpA. The rgpA and rgpB loci on the P. gingivalis chromosome are shown as thick bold lines with the direction of transcription denoted by arrows; mRNA transcripts are shown as thin lines below the genes. Rectangular boxes represent the translation products of the genes and are organized into domains corresponding to propeptide (pro), catalytic domain (α), adhesin domain (β), and C-terminal extension (γ). Sequence differences at the C termini of the α domains of RgpA and RgpB are shown by additional shading on RgpB. Triangles denote proteolytic processing sites on the initial translation products. Carbohydrate modifications to the mature enzymes are indicated by circles (for those which contain the MAb 1B5 determinant), squares, and inverted triangles. Carbohydrate symbols can represent single or multiple oligosaccharide side chains and in the case of HRgpA may be present on either chain or both chains. The double-circle symbols on mt-RgpA and mt-RgpB signify the high level (>30%) of posttranslational addition to these two isoforms.