title: Mycobacterium tuberculosis Rv1096 protein: gene cloning, protein expression, and peptidoglycan deacetylase activity.
abstract: BACKGROUND
  Many bacteria modulate and evade the immune defenses of their hosts through peptidoglycan (PG) deacetylation. The PG deacetylases from Streptococcus pneumonia, Listeria monocytogenes and Lactococcus lactis have been characterized. However, thus far, the PG deacetylase of Mycobacterium tuberculosis has not been identified.
  
  
  RESULTS
  In this study, we cloned the Rv1096 gene from the M. tuberculosis H37Rv strain and expressed Rv1096 protein in both Escherichia coli and M. smegmatis. The results showed that the purified Rv1096 protein possessed metallo-dependent PG deacetylase activity, which increased in the presence of Co2+. The kinetic parameters of the PG deacetylase towards M. smegmatis PG as a substrate were as follows: Km, 0.910 ± 0.007 mM; Vmax, 0.514 ± 0.038 μMmin-1; and Kcat = 0.099 ± 0.007 (S-1). Additionally, the viability of M. smegmatis in the presence of over-expressed Rv1096 protein was 109-fold higher than that of wild-type M. smegmatis after lysozyme treatment. Additionally, light microscopy and scanning electron microscopy showed that in the presence of over-expressed Rv1096 protein, M. smegmatis kept its regular shape, with an undamaged cell wall and smooth surface. These results indicate that Rv1096 caused deacetylation of cell wall PG, leading to lysozyme resistance in M. smegmatis.
  
  
  CONCLUSIONS
  We have determined that M. tuberculosis Rv1096 is a PG deacetylase. The PG deacetylase activity of Rv1096 contributed to lysozyme resistance in M. smegmatis. Our findings suggest that deacetylation of cell wall PG may be involved in evasion of host immune defenses by M. tuberculosis.
authors: Shufeng
authors: S
authors: Yang
authors: Fei
authors: F
authors: Zhang
authors: Jian
authors: J
authors: Kang
authors: Wenli
authors: W
authors: Zhang
authors: Guoying
authors: G
authors: Deng
authors: Yi
authors: Y
authors: Xin
authors: Department of Biochemistry and Molecular Biology, Dalian Medical University, 9 W Lushun South Road, Dalian 116044, China. yufang_ma@hotmail.com.
authors: Yufang
authors: Y
authors: Ma
mesh_terms: D000581:Amidohydrolases / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D003035:Cobalt / Q000378:metabolism; D020536:Enzyme Activators / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D007700:Kinetics; D008854:Microscopy, Electron; D020102:Mycobacterium smegmatis / Q000235:genetics / Q000648:ultrastructure; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000235:genetics; D010457:Peptidoglycan / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D020536:Enzyme Activators; D010457:Peptidoglycan; D011994:Recombinant Proteins; D003035:Cobalt; D000581:Amidohydrolases