Nitric Oxide Synthase 1 (NOS1) Arabidopsis Thaliana Recombinant Protein

Encodes a protein with similarity to the bacterial YqeH GTPase required for proper ribosome assembly. In Arabidopsis, mutant analyses show that this protein regulates growth and hormonal signaling in plants. It also attenuates oxidative stress and reactive oxygen species (ROS). It also seems to be involved in regulating leaf senescence and cell death. This gene product is also involved in nitric oxide biosynthesis in response to ABA but not exogenous H2O2. This protein also appears to be required for proper plastid biogenesis. Levels of several plastid-localized proteins, including RBCL, ClpP1, and the MEP biosynthesis enzymes DXS and DXR are altered in rif1-1 mutants. This protein was originally characterized as a mitrochondrial-localized nitric oxide synthase, but, the synthase activity was later disproven. In addition, new studies with GFP fusion proteins and chloroplast import assays suggest that this protein is found in chloroplasts.

Exhibits cGTPase activity; binds and hydrolyzes specifically GTP (PubMed:18801746). May participate in ribosome assembly and stability and thus regulates protein synthesis in chloroplasts. The GTPase activity requires MgCl2and the presence of either KCl or (NH4)2SO4. Involved in the post-transcriptional regulation of the methylerythritol phosphate (MEP) pathway. Involved in chlorophyll-a fluorescence regulation.