title: Corynebacterium glutamicum possesses β-N-acetylglucosaminidase.
abstract: In Gram-positive Corynebacterium glutamicum and other members of the suborder Corynebacterianeae, which includes mycobacteria, cell elongation and peptidoglycan biosynthesis is mainly due to polar growth. C. glutamicum lacks an uptake system for the peptidoglycan constituent N-acetylglucosamine (GlcNAc), but is able to catabolize GlcNAc-6-phosphate. Due to its importance in white biotechnology and in order to ensure more sustainable processes based on non-food renewables and to reduce feedstock costs, C. glutamicum strains have previously been engineered to produce amino acids from GlcNAc. GlcNAc also is a constituent of chitin, but it is unknown if C. glutamicum possesses chitinolytic enzymes.
  
  
  
  Chitin was shown here not to be growth substrate for C. glutamicum. However, its genome encodes a putative N-acetylglucosaminidase. The nagA 2 gene product was active as β-N-acetylglucosaminidase with 0.27 mM 4-nitrophenyl N,N'-diacetyl-β-D-chitobioside as substrate supporting half-maximal activity. NagA2 was secreted into the culture medium when overproduced with TAT and Sec dependent signal peptides, while it remained cytoplasmic when overproduced without signal peptide. Heterologous expression of exochitinase gene chiB from Serratia marcescens resulted in chitinolytic activity and ChiB secretion was enhanced when a signal peptide from C. glutamicum was used. Colloidal chitin did not support growth of a strain secreting exochitinase ChiB and β-N-acetylglucosaminidase NagA2.
  
  
  
  C. glutamicum possesses β-N-acetylglucosaminidase. In the wild type, β-N-acetylglucosaminidase activity was too low to be detected. However, overproduction of the enzyme fused to TAT or Sec signal peptides led to secretion of active β-N-acetylglucosaminidase. The finding that concomitant secretion of endogenous NagA2 and exochitinase ChiB from S. marcescens did not entail growth with colloidal chitin as sole or combined carbon source, may indicate the requirement for higher or additional enzyme activities such as processive chitinase or endochitinase activities.
authors: Genetics of Prokaryotes, Faculty of Biology & CeBiTec, Bielefeld University, 33501, Bielefeld, Germany.|Present Address: GSK Vaccines S.r.l., Siena, 53100, Italy.
authors: Christian
authors: C
authors: Matano
authors: Institute for Biology and Biotechnology of Plants, WWU Münster University, 48143, Münster, Germany.|Present address: altona Diagnostics GmbH, 22767, Hamburg, Germany.
authors: Stephan
authors: S
authors: Kolkenbrock
authors: Institute for Biology and Biotechnology of Plants, WWU Münster University, 48143, Münster, Germany.
authors: Stefanie N
authors: SN
authors: Hamer
authors: Genetics of Prokaryotes, Faculty of Biology & CeBiTec, Bielefeld University, 33501, Bielefeld, Germany.
authors: Elvira
authors: E
authors: Sgobba
authors: Institute for Biology and Biotechnology of Plants, WWU Münster University, 48143, Münster, Germany.
authors: Bruno M
authors: BM
authors: Moerschbacher
authors: Genetics of Prokaryotes, Faculty of Biology & CeBiTec, Bielefeld University, 33501, Bielefeld, Germany. volker.wendisch@uni-bielefeld.de.
authors: Volker F
authors: VF
authors: Wendisch
mesh_terms: D000117:Acetylglucosamine / Q000378:metabolism; D000118:Acetylglucosaminidase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002686:Chitin / Q000378:metabolism; D002688:Chitinases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D048230:Corynebacterium glutamicum / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D003593:Cytoplasm / Q000201:enzymology / Q000378:metabolism; D004789:Enzyme Activation; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D010457:Peptidoglycan / Q000378:metabolism; D016415:Sequence Alignment; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D010457:Peptidoglycan; D002686:Chitin; C482346:ChiB protein, Serratia marcescens; D002688:Chitinases; D000118:Acetylglucosaminidase; D000117:Acetylglucosamine
keywords: Chitinase; Corynebacterium glutamicum; N-acetylglucosaminidase; NagA2; Secretion