The importance of chitobiase and N-acetylglucosamine (GlcNAc) uptake in N,N'-diacetylchitobiose [(GlcNAc)2] utilization by Serratia marcescens 2170

• Published in: Microbiology (Society for General Microbiology) Vol. 154; no. 5; pp. 1326 - 1332
• Main Authors: Toratani, Tadayuki, Shoji, Toshihiro, Ikehara, Tomonori, Suzuki, Kazushi, Watanabe, Takeshi
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.05.2008; Society for General Microbiology
• Subjects: Bacteriology; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Microbiology; Miscellaneous; Serratia marcescens; Bacteria; Uptake; Serratia marcescens; Enterobacteriaceae
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.2007/016246-0

Department of Applied Biological Chemistry, Faculty of Agriculture, Niigata University, 8050 Ikarashi-2, Niigata 950-2181, Japan Correspondence Takeshi Watanabe wata{at}agr.niigata-u.ac.jp N , N '-diacetylchitobiose [(GlcNAc) 2 ] is the main degradation product from chitin by the action of chitinases of Serratia marcescens 2170. Uptake of (GlcNAc) 2 via a (GlcNAc) 2 -specific enzyme II permease by this bacterium has been demonstrated previously. Here, we report the contribution of chitobiase and N -acetylglucosamine (GlcNAc) uptake to the utilization of (GlcNAc) 2 . When S. marcescens 2170 was cultivated in a medium containing chitin, chitobiase activity was detected both inside and outside the cells; intracellular chitobiase was more abundant and suggested to be mainly located in the periplasm. Production of chitobiase was induced by GlcNAc and more effectively by (GlcNAc) 2 . For induction of chitobiase, uptake of (GlcNAc) 2 was essential but ChiR, an essential regulator of chitinase induction, was not required. S. marcescens 2170 grew well on both GlcNAc and (GlcNAc) 2 but mutants defective in either chitobiase or NagE, the GlcNAc-specific enzyme II permease, showed reduced growth on (GlcNAc) 2 . These results suggest that, in addition to uptake as (GlcNAc) 2 , a proportion of the (GlcNAc) 2 is converted to GlcNAc by chitobiase, mainly in the periplasm, and incorporated into the cytoplasm by NagE. The mutant defective in chitobiase grew more slowly on (GlcNAc) 2 than on GlcNAc, indicating that (GlcNAc) 2 is less efficiently fermented by S. marcescens 2170 in the absence of chitobiase. Therefore, uptake as both (GlcNAc) 2 and GlcNAc is important for efficient utilization of (GlcNAc) 2 in S. marcescens . Abbreviations: GlcNAc, N -acetylglucosamine; (GlcNAc) 2 , N , N '-diacetylchitobiose; 4-MU-GlcNAc, 4-methylumbelliferyl N -acetyl- β - D -glucosaminide; PTS, phosphoenolpyruvate-dependent sugar phosphotransferase system; WS-chitin, water-soluble chitin