In Vitro Studies On The Properties Of Fluorescent Siderophore In Pseudomonas Aeruginosa

Pvd (Pyoverdine), also known as fluorescence siderophore and carries iron transport. It is synthesized and secreted into the environment by many bacteria under the condition of iron deficiency and is a low-molecular-weight ligand with high affinity for ferric ions, making them dissolve and delivere iron ions into the bacterial cell to meet the needs of iron.Pathogenic mechanisms of pseudomonas is associated with iron absorption, regulation; absorption and regulation of iron is closely related with fluorescent siderophore Pvd. Pathogenic process of pseudomonas is very complex and made a wide range of research results, but there many details still remain to be further studied in the absorption and regulation process of iron by Pvd pathway.In this work, we selected the pseudomonas fluorescent siderophore Pvd, rare earth ion Tb3+, bovine serum albumin BSA, human serum albumin HSA and eggs albumin apoOTf three proteins as experimental materials for preliminary study on the interaction of Pvd and Tb3+, the interactions of the small molecule compound Pvd and the three proteins.Firstly, pseudomonas aeruginosa ATCC15692(PAO1) was induced, expressed, purified of Pvd by using molecular biology techniques.The research of fluorescence quenching method and ligand competition law have shown that Pvd can bind with Tb3+by1:1stoichiometric ratio and that the binding process is reversible.Fluorescence thermodynamics and fluorescence lifetime studies have shown that the capacity of binding Tb3+Pvd(Pvd-Tb) combine with BSA is slightly stronger than non-binding Tb3+Pvd and that the binding ratio is still1:1. By calculating the binding constants of BSA to Pvd before and after binding Tb3+, This article proved that the main acting force of Pvd and Pvd-Tb interact with BSA is hydrophobic interactions. In addition, series of thermodynamics parameters of the binding of BSA to Pvd before and after binding Tb3+indicated that the reaction is an exothermic reaction, as well as a spontaneous reaction. Similarly, HSA interact with Pvd similar to BSA, and the capacity of Pvd-Tb combine with HSA is slightly stronger than Pvd. The differences between apoOTf with BSA and HSA are no interaction with Pvd-Tb by composed Pvd with Tb3+. The orders of the binding ability of Pvd and Pvd-Tb with three proteins are:BSA>HSA>apoOTf, and binding capacity orders of three protein with Pvd before and after binding Tb3+is Pvd-Tb>Pvd.Finally, Kinetics studies have illustrated that Pvd can compete out Tb3+of the TbNOTf, OTfTbc and TbNOTfTbc, the binding ability of Pvd and Tb3+more than the combination of apoOTf and Tb3+...