Structural Study Of The Key Proteins In Nicotine Degradation From Pseudomonas Putida S16

Nicotine, as pyridine alkaloid, is well known to be harmful to human health forits ability of crossing blood-brain barrier and biological membranes easily. At thesame time, high concentrations of nicotine can be produced in the process of tobaccoprocessing. In order to safeguard human health and ecological safety, it is urgent tofind a feasible way to reduce the content of nicotine in tobacco and environmentalwaste.Previously, our research group focused on strain Pseudomonas putida S16,which is capable of degrading nicotine. The nicotine degradation pathway of strainS16was confirmed as pyrrolidine pathway which involves a variety of enzymes.6-Hydroxy-3-succinoyl-pyridine hydroxylase (HspB), as one of the key enzymes, isresponsible for catalyzing6-hydroxy-3-succinoyl-pyridine to2,5-dihydroxy-pyridine.In this study, HspB was expressed, purified and crystallized, which will lay afoundation for the research of structure-function relationship.NicR is transcriptional regulation protein in the degradation of nicotine fromStrain S16. NicR belongs to TetR family, which is one of the most commontranscription regulatory factors in pronucleus. NicR was purified, crystal screened andoptimized. We successfully collected X-ray diffraction data by cutting theunconserved sequences of NicR.We could optimize the related proteins involving in nicotine degradation throughthe method of using structural biology to study relationship between protein structureand function, which ether can greatly improve the catalytic efficiency of enzymes orchange their specificity. It not only has the vital significance on the study of nicotinemetabolic pathway, but also may have the prospect of industrial application, whichcontributes to human health and environmental protection.