Specific DNA recognition mediated by a type IV pilin

Abstract

Natural transformation is a dominant force in bacterial evolution by promoting horizontal gene transfer. This process may have devastating consequences, such as the spread of antibiotic resistance or the emergence of highly virulent clones. However, uptake and recombination of foreign DNA are most often deleterious to competent species. Therefore, model naturally transformable Gramnegative bacteria, including the human pathogen Neisseria meningitidis, have evolved means to preferentially take up homotypic DNA containing short and genus-specific sequence motifs. Despite decades of intense investigations, the DNA uptake sequence receptor in Neisseria species has remained elusive. We show here, using a multidisciplinary approach combining biochemistry, molecular genetics, and structural biology, that meningococcal type IV pili bind DNA through the minor pilin ComP via an electropositive stripe that is predicted to be exposed on the filaments surface and that ComP displays an exquisite binding preference for DNA uptake sequence. Our findings illuminate the earliest step in natural transformation, reveal an unconventional mechanism for DNA binding, and suggest that selective DNA uptake is more widespread than previously thought.DNA receptor | genetic competence

Kinetics of DNA uptake during transformation provide evidence for a translocation ratchet mechanism

“…We show that the force-dependent kinetics of DNA uptake are in remarkable agreement with a translocation ratchet model, whereby the periplasmic ComE protein acts as a chaperone that rectifies DNA diffusion through the outer membrane by reversible binding. strongly inhibited when comP is deleted (31,32). PilV has an antagonistic character, and its deletion increases the probability for DNA binding and uptake (33).…”

Isolation and characterization of Neisseria musculi sp. nov., from the wild house mouse

“…Playing important roles in this process are the Type IV pilus (Tfp) and the DUS, a 10 nt sequence, 5¢-GCCGTCTGAA-3¢, that is highly enriched in neisserial genomes. Tfp-mediated DNA transformation involves, among other things, the binding of the DUS to Tfpassociated protein ComP, and PilT-driven retraction of the Tfp (Cehovin et al, 2013;Hamilton & Dillard, 2006;Wolfgang et al, 1998). Two DUS variants, distinguished by two bases immediately preceding the 10-mer, are abundant in neisserial genomes: 5¢-agGCCGTCTGAA-3¢ and 5¢-atGCCG TCTGAA-3¢.…”

“…Tfp consists of a fibre, composed mainly of pilin subunits, that extends from the cell into the extracellular milieu, and machinery for its assembly and many biological activities (Carbonnelle et al, 2006;Giltner et al, 2012). In addition to DNA tranformation (Cehovin et al, 2013;Wolfgang et al, 1998), Tfp plays important roles in other aspects of biology of the genus Neisseria, including bacterial attachment, motility, microcolony formation and signalling to the host cell (Eriksson et al, 2012;Helaine et al, 2005;Higashi et al, 2007;Howie et al, 2005;Kurre et al, 2012;Lee et al, 2005;Merz et al, 1996Merz et al, , 1999Merz et al, , 2000Nassif et al, 1994;Pujol et al, 1999;Winther-Larsen et al, 2001;Wolfgang et al, 1998). That AP2031 T /N.…”

Genetics of Natural Competence in Vibrio cholerae and other Vibrios

“…The ComP protein in N. meningitidis has been identified as a likely DUS receptor with higher binding affinity for species-specific sequence than for nonspecific sequence (22). V. cholerae does not appear to restrict uptake to species-specific DNA, as Suckow et al have demonstrated the capacity of V. cholerae to take up DNA from other bacteria, such as Escherichia coli, into the periplasmic space between the IM and OM (23).…”