title: Characterization of Burkholderia pseudomallei protein BPSL1375 validates the Putative hemolytic activity of the COG3176 N-Acyltransferase family.
abstract: BACKGROUND
  There are still numerous protein subfamilies within families and superfamilies that do not yet have conclusive empirical experimental evidence providing a specific function. These proteins persist in databases with the annotation of a specific 'putative' function made by association with discernible features in the protein sequence.
  
  
  RESULTS
  Here, we report the characterization of one such protein produced by the pathogenic soil bacterium Burkholderia pseudomallei, BPSL1375, which provided evidence for putative hemolysins in the COG3176 family to have experimentally validated hemolytic activity. BPSL1375 can be classified into the N-acyltransferase superfamily, specifically to members of the COG3176 family. Sequence alignments identified seven highly conserved residues (Arg54, Phe58, Asp75, Asp78, Arg99, Glu132 and Arg135), of which several have been implicated with N-acyltransferase activity in previously characterized examples. Using the 3D model of an N-acyltransferase example as a reference, an acyl homoserine lactone synthase, we generated 3D structure models for mutants of six of the seven N-acyltransferase conserved residues (R54, D75, D78, R99, E132 and R135). Both the R99 and R135 mutants resulted in a loss of hemolytic activity while mutations at the other five positions resulted in either reduction or increment in hemolytic activity.
  
  
  CONCLUSIONS
  The implication of residues previously characterized to be important for N-acyltransferase activity to hemolytic activity for the COG3176 family members of the N-acyltransferase provides validation of the correct placement of the hemolytic capability annotation within the N-acyltransferase superfamily.
authors.affiliation: School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia. laziana@mfrlab.org.
authors.forename: Laziana
authors.initials: L
authors.lastname: Ahmad
authors.affiliation: School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia. teng@mfrlab.org.
authors.forename: Teng Loong
authors.initials: TL
authors.lastname: Hung
authors.affiliation: School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia. azurah@mfrlab.org.|Malaysia Genome Institute, 43000, Kajang, Selangor, Malaysia. azurah@mfrlab.org.
authors.forename: Nor Azurah
authors.initials: NA
authors.lastname: Mat Akhir
authors.affiliation: School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia. rahmah.mohamed@newinti.edu.my.|INTI International University, Bandar Baru Nilai, Nilai, Negeri Sembilan, 71800, Malaysia. rahmah.mohamed@newinti.edu.my.
authors.forename: Rahmah
authors.initials: R
authors.lastname: Mohamed
authors.affiliation: School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia. sheila@ukm.edu.my.
authors.forename: Sheila
authors.initials: S
authors.lastname: Nathan
authors.affiliation: School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia. firdaus@mfrlab.org.|Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia. firdaus@mfrlab.org.
authors.forename: Mohd
authors.initials: M
authors.lastname: Firdaus-Raih
mesh_terms: D000217:Acyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D001120:Arginine / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D016957:Burkholderia pseudomallei / Q000235:genetics / Q000378:metabolism*; D017124:Conserved Sequence; D004912:Erythrocytes / Q000187:drug effects; D006460:Hemolysin Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D008958:Models, Molecular; D005810:Multigene Family; D009154:Mutation; D011817:Rabbits; D012756:Sheep / Q000097:blood; D012988:Soil Microbiology
chemical_list: D001426:Bacterial Proteins; D006460:Hemolysin Proteins; D001120:Arginine; D000217:Acyltransferases