The ‘captain of the men of death’, Streptococcus pneumoniae, fights oxidative stress outside the ‘city wall’

In proteins, the sulfur‐containing amino acids cysteine and methionine are very susceptible to oxidation, which can lead to protein inactivation or degradation. [...]S. pneumoniae possesses widely conserved repair systems to cope with oxidative damage inflicted to proteins. Accumulating evidence has shown that scavenging and repair systems are of extreme importance for bacteria to cope with their environment and with the immune response. [...]repair enzymes such as Trx and Msr have been demonstrated to play a role in the virulence of pathogens such as Mycobacterium tuberculosis and Salmonella typhimurium (Bjur et al, ; Denkel et al, ; Lee et al, ). [...]of particular interest would be the identification of the substrates of SpMsrAB2 that need reduction of their oxidized methionines. [...]it would be judicious to further investigate the impact of extracytoplasmic reducing systems on the virulence of other major pathogens, these systems being the first line of defence towards the exogenous oxidative stress encountered during the immune response.