To test the hypothesis that Hmp overexpression , and not that of other NsrR-regulated gene products ( such as ytfE , hcp -- hcr , tehA , tehB and ygbA ) is responsible for hypersensitivity to peroxynitrite , we determined the effect of peroxynitrite on a double mutant ( hmp and nsrR ) .
A novel NsrR-regulated gene designated STM1808 has been identified , along with hmp , hcp-hcr , yeaR-yoaG , ygbA and ytfE .
To determine the contribution of other NsrR-regulated genes to nitrosative-stress resistance , we constructed insertion mutations in hcp , ygbA , ytfE , STM1808 and yeaR ( Experimental Procedures ) .
These include the NsrR-regulated ygbA , yeaR-yoaG and STM1808 genes ( Bang , 2006 ; Gilberthorpe et al. , 2007 ; Karlinsey et al. , 2012 ; Rodionov et al. , 2005 ) .