Corynebacterium glutamicum possesses β-N-acetylglucosaminidase

BMC Microbiology

Research Article

Elvira Sgobba¹  Volker F. Wendisch¹  Christian Matano²  Bruno M. Moerschbacher³  Stefanie N. Hamer³  Stephan Kolkenbrock⁴ 

[1] Genetics of Prokaryotes, Faculty of Biology & CeBiTec, Bielefeld University, 33501, Bielefeld, Germany;Genetics of Prokaryotes, Faculty of Biology & CeBiTec, Bielefeld University, 33501, Bielefeld, Germany;Present Address: GSK Vaccines S.r.l., 53100, Siena, Italy;Institute for Biology and Biotechnology of Plants, WWU Münster University, 48143, Münster, Germany;Institute for Biology and Biotechnology of Plants, WWU Münster University, 48143, Münster, Germany;Present address: altona Diagnostics GmbH, 22767, Hamburg, Germany;

关键词: NagA;    N-acetylglucosaminidase;    Corynebacterium glutamicum;    Secretion;    Chitinase;   

DOI  :  10.1186/s12866-016-0795-3

 received in 2016-01-16, accepted in 2016-07-30,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundIn 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.ResultsChitin was shown here not to be growth substrate for C. glutamicum. However, its genome encodes a putative N-acetylglucosaminidase. The nagA2 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.ConclusionsC. 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.

【 授权许可】

CC BY   
© The Author(s). 2016