Study On The Locations Of L11's Methylation And The Founction In Leptospira Interrogans

The leptospirosis is a widely spread disease of global concern and a whole genome of Leptospira interrogans(L.interrogans) has been aequenced.L11 is one of ribosomal proteins which 23S ribosomal RNA bound to .L11 regulates the assembly of Ribosome and affects the protein expression. In ordor to characterize the locations and functions of L11 's methlyation .A L.interrogans genomic DNA was used as template to amplify the Full-length of ribosomal protein L11 methyltransferase (liprmA) , liL11 and liL11 mutants by PCR, which were inserted into a prokaryotic expression vectors: pET22b-PrmA , pET28a-liL11, pET28a-liL11-â–³2, pET28a-liL11-â–³4, pET28a-liL11-I , pET28a-liL11-II, pET28a-liL11-III, pET28a-liL11-IV, pET28a-liL11-V , and analyzed the best expression conditions of PrmA. All the proteins were purified.The liL11 ,liL11 mutuants reacted with PrmA under the present of S-adenosyl-methionine[³H] respectively . To characterize the functions of liL11 methylation under sanlinity stress. 3 treatment salinity levels were set up for this study which were 1% , 2%, 3% NaCl respectively. The growth of E.coli with pET28a, pET-28aliL11, pET-28aliL11-â–³4 under high salinity were observed. The results suggested that: (1) The best inducement conditions of PrmA were:E.coli with pET22b-PrmA was cultured under 37℃,200r/min until OD₆₀₀=0.6 before induced ,then was induced by 0.6 M IPTG for 12hours under 25 ℃. (2) liL11 contains 4 methl groups Lys3,Lys4,Lys7,Lys10 in L.interrogans according to the result of autoradiography. (3) The growth of E.coli with pET28a-liL11 were more than the one with pET 28a-liL11-â–³4 by 21% or 22% under 2% or 3% NaCl conditions respectively, liLll methylation could promote the growth of E.coli under high salinity.