A glutathione-based system for defense against carbonyl stress in Haemophilus influenzae
1 Research Centre for Infectious Disease, School of Molecular and Biomedical Science, The University of Adelaide, North Terrace Campus, Adelaide, 5005, Australia
2 Institute for Glycomics, Griffith University (Gold Coast Campus), Parklands Drive, Southport, Queensland, 4215, Australia
3 School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, 4072, Australia
BMC Microbiology 2012, 12:159 doi:10.1186/1471-2180-12-159Published: 31 July 2012
adhC from Haemophilus influenzae encodes a glutathione-dependent alcohol dehydrogenase that has previously been shown to be required for protection against killing by S-nitrosoglutathione (GSNO). This group of enzymes is known in other systems to be able to utilize substrates that form adducts with glutathione, such as aldehydes.
Here, we show that expression of adhC is maximally induced under conditions of high oxygen tension as well as specifically with glucose as a carbon source. adhC could also be induced in response to formaldehyde but not GSNO. An adhC mutant was more susceptible than wild-type Haemophilus influenzae Rd KW20 to killing by various short chain aliphatic aldehydes, all of which can be generated endogenously during cell metabolism but are also produced by the host as part of the innate immune response.
These results indicate that AdhC plays a role in defense against endogenously generated reactive carbonyl electrophiles in Haemophilus influenzae and may also play a role in defense against the host innate immune system.