Effects Of Nitirc Oxide On Activity And Gene Expression Of Soluble Guanylate Cyclase From Peach Fruits

Feicheng peach is one of a famous specialty of fruits in China. But after harvest, the fruit aredifficult to store for its easily perishable character. The importance of nitric oxide (NO) as asignaling molecule are drawing more and more attention. Soluble guanylate cyclase (sGC) is thereceptor of NO involved in the NO/cGMP signal transduction regulation, and its significanceshould not be overlooked. Studying of the molecular biology of the peach fruit play an importantrole in the quality improvement and genetic breeding.In this study, a cDNA encoding sGC protein was isolated from Feicheng peach fruits byRT-PCR and rapid amplification of cDNA ends (RACE). The full-length cDNA of sGC was1527bp and contained852bp of the coding sequence encoding a polypeptide of283amino acids.Homologous analysis showed that the homology of sGC of Feicheng peach fruit compared withsGC of Arabidopsis thaliana was highest by69%. Evolutionary tree clustering analysis indicatedthat the genetic distances between Feicheng peach sGC protein and sGC in Glycine max andMedicago truncatula were the shortest, respectively. To collect the evidence for the influence ofNO on sGC and the protein, the enzyme with sGC activity were isolated from Feicheng peachfruits and the cGMP content and activity of sGC were analysed. The achieved results showed thatNO could increase the activity of sGC. Results of real time PCR and electrochemical experimentshowed that NO could promote sGC expression and change the conformation of sGC proteinunder the certain conditions. Furthermore, the optimum conditions of4mmol L-1GTP, pH7.6and25oC for sGC protein activity were obtained by using high performance liquid chromatography(HPLC).