1.9.6.1	C176S	mutation in strictly conserved residue, significantly lower activity than wild-type	
1.9.6.1	K56H	11% of wild-type activity at pH 7	
1.9.6.1	K56M	5% of wild-type activity at pH 7	
1.9.6.1	additional information	the physiological role of NAP in nitrate metabolism is investigated in studies with a mutant bearing a transposon insertion in one of the structural genes	
1.9.6.1	additional information	constructin of a napA mutant strain CAL277, and of several other nap gene mutants, overview	
1.9.6.1	additional information	construction of a gene nap deletion mutant, the wild-type gene is replaced by the deletion/insertion version via homologous recombination. The mutant strain can no longer grow on methanol in contrast to the wild-type	
1.9.6.1	additional information	genotyping of different strains from M and G populations, overview. The only mutated gene shared between the strains from populations M and G is bll4572, this gene encodes the Bll4572 protein and is mutated in all six strains. Regulation of nos and nap genes by the NasST system in the absence or presence of nitrate in mutant strains, overview. NasS and NasT form a stable complex that is sensitive to the presence of NO3-/NO2-. Binding of NO3-/NO2- by the sensor NasS triggers the release of NasT, which binds the leader sequence upstream of the nas operon, thereby preventing hairpin formation and allowing complete transcription of the nas operon	
1.9.6.1	S4C/S24C	site-directed mutagenesis, native, NapD results in a loss of some of the spin labels from the NapA signal peptide possibly due to the surface-exposed native cysteine residues of NapD. The NapD cysteine residues (C8 and C32) are not conserved and a cysteine-free variant of NapD complements a DELTAnapD strain for restoration of NapA activity. A NapD C8S/C32A variant remains attached to the NapA signal peptide