%0 Journal Article
%T Identification of critical residues of the serotype modifying O-acetyltransferase of Shigella flexneri
%A Farzaana Thanweer
%A Naresh K Verma
%J BMC Biochemistry
%D 2012
%I BioMed Central
%R 10.1186/1471-2091-13-13
%X In this study, the conserved motifs in the TM regions and in hydrophilic loops of S. flexneri Oac were targeted for mutagenesis with the aim of identifying the amino acid residues essential for the function of Oac. We previously identified three critical arginines每R73, R75 and R76 in the cytoplasmic loop 3 of Oac. Re-establishing that these arginines are critical, in this study we suggest a catalytic role for R73 and a structural role for R75 and R76 in O-acetylation. Serine-glycine motifs (SG 52每53, GS 138每139 and SYG 274每276), phenylalanine-proline motifs (FP 78每79 and FPV 282每84) and a tryptophan-threonine motif (WT141-142) found in TM segments and residues RK 110每111, GR 269每270 and D333 found in hydrophilic loops were also found to be critical to Oac function.By studying the effect of the mutations on Oac＊s function and assembly, an insight into the possible roles played by the chosen amino acids in Oac was gained. The transmembrane serine-glycine motifs and hydrophilic residues (RK 110每111, GR 269每270 and D333) were shown to have an affect on Oac assembly which suggests a structural role for these motifs. The phenylalanine-proline and the tryptophan-threonine motifs affect Oac function which could suggest a catalytic role for these amino acids.
%K Shigella flexneri
%K O-acetyltransferase (Oac)
%K Critical amino acids
%U http://www.biomedcentral.com/1471-2091/13/13/abstract