A Preliminary Study On Structure Of MarR Family Protein Rv0880 In Mycobacterium Tuberculosis

Tuberculosis is a chronic respiratory infection caused by Mycobacterium Tuberculosis(M.tb)which can lead to death at the worst.In recent years,because of the unreasonable use of anti-TB drugs,the ratio of drug resistance strains increased year by year.Therefore,exploring the molecular mechanism of drug resistance of M.tb has become an important strategy for the treatment of tuberculosis.Multiple antibiotic resistance regulators family protein(MarR)is a kind of transcriptional regulation protein,there are few reports about this family protein in M.tb.Salicylate is a typical ligand of MarR family protein.In addition,salicylate can reduce the susceptibility of M.tb to a variety of anti-TB drugs,but the specific mechanism of this phenomenon is still not very clear.According to this,we speculated that MarR family proteins plays a certain role in M.tb's drug resistance to Salicylate.Rv0880 of MarR family proteins is selected as the research object,and a preliminary study about its structure and function had been done.The gene Rv0880 from the genome of M.tb H37Rv has been amplified,and the recombinant fused expression plasmid pET28a-Rv0880 was constructed.The result showed the fusion protein can expressed highly in it.Western Blot indicated Rv0880 was exressed correctly with N-end His-tag.Then crystallize with the highly purified recombinant protein,the diamond-shaped crystal was got after screen and optimization.The crystal diffraction data with 2.6 A resolution has been collected by X-ray diffraction,the mosflm program was used to process our data.The result showed that the crystals of Rv0880 belongs to space group P1 and unit-cell parameters were a=54.9701,b=69.5998,c=70.3204,a=103.71°,?=111.06°,?vc=105.83°.But the structure analysis by Molecular Replacement dose failed because of the phase lag.So the seleno-methionine derivant of Rv0880 is successfully made and the diffraction data was good,the structure analysis by Multi-wavelength Anomalous Dispersion is in the process.Moreover,the interaction between Rv0880 and salicylate and structurally-related compounds were investigated by Differential Scanning Fluorimetry and Isothermal Titration Calorimetry.But the result showed that salicylate and structurally-related compounds have no interactions with Rv0880.Further research about the role Rv0880 plays in the drug resistance of M.tb caused by Salicylate needs to be done.