dc.contributor.author |
Chalmers, Callum |
en |
dc.contributor.author |
Khemlani, AHJ |
en |
dc.contributor.author |
Sohn, CR |
en |
dc.contributor.author |
Hughes, Jacelyn |
en |
dc.contributor.author |
Tsai, Jia Yun |
en |
dc.contributor.author |
Proft, Thomas |
en |
dc.coverage.spatial |
Nadi, Fiji |
en |
dc.date.accessioned |
2018-11-21T21:48:38Z |
en |
dc.date.issued |
2017 |
en |
dc.identifier.issn |
1684-1182 |
en |
dc.identifier.uri |
http://hdl.handle.net/2292/44537 |
en |
dc.description.abstract |
BACKGROUND: Streptococcus pyogenes, or Group A Streptococcus (GAS), is a human pathogen that causes a wide range of diseases, including pharyngitis, necrotizing fasciitis and toxic shock syndrome. The bacterium produces a large arsenal of virulence factors, including the cell wall-anchored Streptococcus pyogenes nuclease A (SpnA), which facilitates immune evasion by degrading the DNA backbone of neutrophil extracellular traps. SpnA consists of a C-terminal endo/exonuclease domain and a N-terminal domain of unknown function. METHODS: Recombinant SpnA mutants were generated by alanine conversion of selected residues that were predicted to play a role in the enzymatic activity and tested for their ability to degrade DNA. A GAS spnA deletion mutant was complemented with a plasmid-borne catalytic site mutant and analyzed for virulence in a Galleria mellonella (wax moth) infection model. RESULTS: Several predicted residues were experimentally confirmed to play a role in SpnA enzymatic activity. These include Glu592, Arg696, His716, Asp767, Asn769, Asp810 and Asp842. Complementation of a GAS spnA deletion mutant with a spnA H716A mutant gene partially restored virulence in wax moth larvae, whereas complementation with the spnA wt gene completely restored activity. Furthermore, complementation with a secreted form of SpnA showed reduced virulence. CONCLUSION: Our results show that abolishing the enzymatic activity of SpnA only partially reduces virulence suggesting that SpnA has an additional virulence function, which might be located on the N-terminal domain. Furthermore, cell wall-anchoring of SpnA results in higher virulence compared to secreted SpnA, probably due to a higher local density of the enzyme. |
en |
dc.publisher |
Elsevier |
en |
dc.relation.ispartofseries |
Journal of Microbiology, Immunology and Infection |
en |
dc.rights |
Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. |
en |
dc.rights.uri |
https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm |
en |
dc.title |
Streptococcus pyogenes nuclease A (SpnA) mediated virulence does not exclusively depend on nuclease activity |
en |
dc.type |
Journal Article |
en |
dc.identifier.doi |
10.1016/j.jmii.2017.09.006 |
en |
dc.rights.holder |
Copyright: The author |
en |
dc.identifier.pmid |
29158081 |
en |
dc.rights.accessrights |
http://purl.org/eprint/accessRights/RestrictedAccess |
en |
pubs.subtype |
Article |
en |
pubs.elements-id |
700865 |
en |
pubs.org-id |
Medical and Health Sciences |
en |
pubs.org-id |
Medical Sciences |
en |
pubs.org-id |
Molecular Medicine |
en |
pubs.org-id |
Science |
en |
pubs.org-id |
Science Research |
en |
pubs.org-id |
Maurice Wilkins Centre (2010-2014) |
en |
pubs.record-created-at-source-date |
2017-10-26 |
en |
pubs.dimensions-id |
29158081 |
en |