| Title: | "PrgK, a multidomain peptidoglycan hydrolase, is essential for conjugative transfer of the pheromone-responsive plasmid pCF10" |
| Author(s): | Laverde Gomez JA; Bhatty M; Christie PJ; |
| Address: | "Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, Houston, Texas, USA" |
| ISSN/ISBN: | 1098-5530 (Electronic) 0021-9193 (Print) 0021-9193 (Linking) |
| Abstract: | "Peptidoglycan (PG) hydrolases associated with bacterial type IV secretion systems (T4SSs) are thought to generate localized lesions in the PG layer to facilitate assembly of the translocation channel. The pheromone-responsive plasmid pCF10 of Enterococcus faecalis encodes a putative cell wall hydrolase, PrgK, and here we report that a prgK deletion abolished functionality of the pCF10-encoded T4SS as monitored by pCF10 conjugative transfer. Expression in trans of wild-type prgK fully complemented this mutation. PrgK has three potential hydrolase motifs resembling staphylococcal LytM, soluble lytic transglycosylase (SLT), and cysteine-, histidine-dependent amidohydrolase/peptidase (CHAP) domains. Complementation analyses with mutant alleles established that PrgK bearing two hydrolase domains in any combination supported near-wild-type plasmid transfer, and PrgK bearing a single hydrolase domain supported at least a low level of transfer in filter matings. When exported to the Escherichia coli periplasm, each domain disrupted cell growth, and combinations of domains additionally induced cell rounding and blebbing and conferred enhanced sensitivity to osmotic shock. Each domain bound PG in vitro, but only the SLT domain exhibited detectable hydrolase activity, as shown by zymographic analyses and release of fluorescent PG fragments. Genes encoding three T4SS-associated, putative hydrolases, Lactococcus lactis CsiA, Tn925 Orf14, and pIP501 TraG, partially complemented the DeltaprgK mutation. Our findings establish that PrgK is an essential component of the pCF10-encoded Prg/Pcf T4SS and that its hydrolase domains coordinate their activities for full PrgK function. PrgK is indispensable for plasmid transfer in liquid matings, suggestive of a role in formation or stabilization of mating junctions" |
| Keywords: | "Bacterial Proteins/genetics/metabolism Enterococcus faecalis/*enzymology/genetics/metabolism Gene Expression Regulation, Bacterial/*physiology Gene Expression Regulation, Enzymologic Mutation N-Acetylmuramoyl-L-alanine Amidase/*classification/genetics/met;" |
| Notes: | "MedlineLaverde Gomez, Jenny A Bhatty, Minny Christie, Peter J eng R01 GM048746/GM/NIGMS NIH HHS/ R21 AI105454/AI/NIAID NIH HHS/ 2R01GM048476/GM/NIGMS NIH HHS/ 1R21AI105454/AI/NIAID NIH HHS/ Research Support, N.I.H., Extramural 2013/11/19 J Bacteriol. 2014 Feb; 196(3):527-39. doi: 10.1128/JB.00950-13. Epub 2013 Nov 15" |
