Identification and Characterization of a Novel Polysaccharide Deacetylase C (PdaC) from Bacillus subtilis

• Published in: The Journal of biological chemistry 2012-03, Vol.287 (13), p.9765-9776
• Main Authors: Kobayashi, Kaori, Sudiarta, I Putu, Kodama, Takeko, Fukushima, Tatsuya, Ara, Katsutoshi, Ozaki, Katsuya, Sekiguchi, Junichi
• Format: Article
• Language: English
• Subjects: Bacillus; Bacillus subtilis - enzymology; Bacillus subtilis - genetics; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Cell Surface Enzymes; Enzymes; Enzymology; Escherichia coli - enzymology; Escherichia coli - genetics; Esterases - chemistry; Esterases - genetics; Esterases - metabolism; Gene Deletion; Kinetics; Lysozyme Sensitivity; Microbiology; Peptidoglycan; Peptidoglycan - chemistry; Peptidoglycan - genetics; Peptidoglycan - metabolism; Sequence Homology, Amino Acid; Streptococcus pneumoniae - enzymology; Streptococcus pneumoniae - genetics
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M111.329490

Cell wall metabolism and cell wall modification are very important processes that bacteria use to adjust to various environmental conditions. One of the main modifications is deacetylation of peptidoglycan. The polysaccharide deacetylase homologue, Bacillus subtilis YjeA (renamed PdaC), was characterized and found to be a unique deacetylase. The pdaC deletion mutant was sensitive to lysozyme treatment, indicating that PdaC acts as a deacetylase. The purified recombinant and truncated PdaC from Escherichia coli deacetylated B. subtilis peptidoglycan and its polymer, (-GlcNAc-MurNAc[-l-Ala-d-Glu]-)n. Surprisingly, RP-HPLC and ESI-MS/MS analyses showed that the enzyme deacetylates N-acetylmuramic acid (MurNAc) not GlcNAc from the polymer. Contrary to Streptococcus pneumoniae PgdA, which shows high amino acid sequence similarity with PdaC and is a zinc-dependent GlcNAc deacetylase toward peptidoglycan, there was less dependence on zinc ion for deacetylation of peptidoglycan by PdaC than other metal ions (Mn2+, Mg2+, Ca2+). The kinetic values of the activity toward B. subtilis peptidoglycan were Km = 4.8 mm and kcat = 0.32 s−1. PdaC also deacetylated N-acetylglucosamine (GlcNAc) oligomers with a Km = 12.3 mm and kcat = 0.24 s−1 toward GlcNAc4. Therefore, PdaC has GlcNAc deacetylase activity toward GlcNAc oligomers and MurNAc deacetylase activity toward B. subtilis peptidoglycan. Peptidoglycan modification is a very important process that bacteria use to adjust to various environmental conditions. B. subtilis pdaC was associated with lysozyme sensitivity. Surprisingly PdaC is able to deacetylate N-acetylmuramic acid but not N-acetylglucosamine in peptidoglycan. But chitin oligomers were deacetylated by PdaC. PdaC is a unique enzyme exhibiting two different deacetylase activities. Novel deacetylase is characterized.