Neisseria gonorrhoeae
Peter M. Lydyard, Michael F. Cole, John Holton, William L. Irving, Nino Porakishvili, Pradhib Venkatesan, Katherine N. Ward in Case Studies in Infectious Disease, 2010
The pilin (PilE) protein contains a constant N-terminal domain, a hyper-variable C-terminal domain, and several variable regions termed mini-cassettes, which are encoded by genes with varying DNA sequence. The gonococcus has a single complete copy of the pilin gene termed pilE but as many as 15 truncated genes with variable DNA sequence. The truncation is at the 5′ end, resulting in lack of the sequence encoding the N-terminal constant domain and promoter elements. These truncated genes are termed pilS (silent) and form the pilS locus. By recombination of pilS sequences into the pilE gene the bacterium can express a high number of antigenically distinct pili. In addition to antigenic variation the pili undergo phase variation. In phase variation the bacterium has the ability to turn pilus expression on or off at a high frequency.
Pili and Hosts
Paul Pumpens in Single-Stranded RNA Phages, 2020
These conjugative plasmids from Gram-negative bacteria directed the synthesis of the extracellular pili which had an essential role in the recognition of recipient cells and the establishment of cell-to-cell contact, as well in the adsorption of the RNA phages. The pilin subunits, namely the structural units of the pili, often shared no similarity. For simplicity, pili were classified into two broad morphological groups: long flexible (1 μm) and short rigid (0.1 μm). Long pili were like those expressed by cells carrying the F plasmid. Short pili were expressed by plasmids of the IncN, IncP, and IncW incompatibility groups. Some plasmids (Inc groups I1, I2, I5, B, K, and Z) encoded both long and short pili (Encyclopedia of Life Sciences, 2008, p. 2208).
Host Defense II: Acquired Immunity
Constantin A. Bona, Francisco A. Bonilla in Textbook of Immunology, 2019
Borrelia burgdorferi (which causes Lyme disease) possesses about 25 copies of genes encoding the immunodominant variable major protein. It also appears to undergo genetic drift in the Osp B outer membrane protein. Neisseria gonorrheae pili are a major target for antibody production. The pilin protein is also encoded by multiple genes which are sequentially activated. Gonococci use a similar mechanism where new genes are inserted into an expression site. However, this bacterium often uses exogenous DNA from dead disrupted gonococci for gene conversion.
High throughput and targeted screens for prepilin peptidase inhibitors do not identify common inhibitors of eukaryotic gamma-secretase
Published in Expert Opinion on Drug Discovery, 2023
Pradip Kumar Singh, Michael S. Donnenberg
Type 4 pili (T4P) are retractile filamentous surface appendages present in numerous Gram-positive and Gram-negative bacteria as well as archaea [1–3]. T4P have many functions, including twitching motility, surface attachment, DNA uptake, biofilm formation, host colonization, auto-aggregation, and environmental sensing. In several bacterial pathogens, such as enteropathogenic Escherichia coli (EPEC), Vibrio cholerae, Pseudomonas aeruginosa, Neisseria meningitidis, N. gonorrhoeae, and Clostridioides difficile, T4P may play a role in pathogenesis [4,5]. The T4P of EPEC and V. cholerae are proven virulence factors in experimental human infection [6,7]. The filament of T4P is composed of pilin proteins in a helical array, and its biogenesis requires a complex multi-protein machine that spans the cytoplasmic membrane and, in Gram-negative bacteria, the outer membrane [8]. Pilin protein is synthesized as a prepilin, which has a class III N-terminal signal peptide sequence. Cleavage of this signal sequence is required before the pilin can be incorporated into the growing pilus [9–11]. A dedicated prepilin peptidase (PPP) cleaves the leader sequence of the prepilin and, in many cases, methylates the nascent N-terminal residue [12–14]. Deletion or active-site mutations in PPP genes preclude T4P expression [11,13,15,16].
Improving protein glycan coupling technology (PGCT) for glycoconjugate vaccine production
Published in Expert Review of Vaccines, 2020
Jennifer Mhairi Dow, Marta Mauri, Timothy Alexander Scott, Brendan William Wren
PglL was first described in Neisseria meningitidis where it glycosylates its native substrate PilE (type IV pilin). The PglL family of enzymes is more promiscuous than PglBs as they do not require an acetamido group modification at the reducing end of the polysaccharide and can also transfer glycans with a galactose reducing end sugar [56,57]. An 8-amino acid PglL consensus glycosylation sequon has been identified and exploited since then to produce conjugate vaccines against Shigella flexneri 2a, Salmonella enterica sv. Paratyphi and Brucella abortus [58,59,137].
The adhesins of non-typeable Haemophilus influenzae
Published in Expert Review of Anti-infective Therapy, 2018
Karen L. Osman, Johanna M. Jefferies, Christopher H. Woelk, David W. Cleary, Stuart C. Clarke
The type IV pilin (Tfp) is encoded by genes pilA-D and comA-F in NTHi with the major pili protein being encoded by pilA. High adherence to ICAM-1 on epithelial cells has been associated with the type IV pili [83]. Significant reduction in adherence to human bronchial epithelial cells has been reported in mutants of all pil and com genes, responsible for the expression of the Tfp, except comC [84]. Furthermore, the type IV pili has been demonstrated as important for formation and structural maintenance of the NTHi biofilm [57,79,84,85].
Related Knowledge Centers
- Bacteria
- Cell Adhesion
- Pilus
- Polymer
- Protein
- Pathogen
- Gene
- Gram-Negative Bacteria
- Protein–Protein Interaction
- Gram-Positive Bacteria