Sugar Transport by the Marine Chitinolytic Bacterium Vibrio furnissii: MOLECULAR CLONING AND ANALYSIS OF THE GLUCOSE AND N-ACETYLGLUCOSAMINE PERMEASES

Carolyn L Bouma,Saul Roseman

doi:10.1074/jbc.271.52.33457

Carolyn L Bouma, Saul Roseman

Open Access

https://doi.org/10.1074/jbc.271.52.33457

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Abstract

Chitin catabolism by the marine bacterium Vibrio furnissii involves chemotaxis to and transport of N-acetyl-D-glucosamine (GlcNAc) and D-glucose. We report the properties of the respective permeases that complemented E. coli Glc- Man- mutants. Although the V. furnissii Glc-specific permease (55,941 Da) shares 38% identity with E. coli IIGlc (ptsG), it is 67% identical to MalX of the E. coli maltose operon (Reidl, J., and Boos, W. (1991) J. Bacteriol. 173, 4862-4876). An adjacent open reading frame encodes a protein with 52% identity to E. coli MalY. Glc phosphorylation requires only V. furnissii MalX and the accessory phosphoenolpyruvate:glycose phosphotransferase system proteins. The V. furnissii equivalent of IIGlc was not found in the 25,000 transformants screened. The GlcNAc/Glc-specific permease (52,894 Da) shares 47% identity with the N-terminal, hydrophobic domain of E. coli IINag, but is unique among IINag proteins in that it lacks the C-terminal domain and thus requires IIIGlc for sugar fermentation in vivo and phosphorylation in vitro. While there are similarities between the phosphoenolpyruvate:glycose phosphotransferase system of V. furnissii and enteric bacteria, the differences may be important for survival of V. furnissii in the marine environment.

Highlights

Chitin, a b,134-linked polymer of N-acetylglucosamine (GlcNAc), is one of the most abundant organic compounds in nature
Degradation of chitin by V. furnissii is initiated by chitinases that hydrolyze it to soluble oligosaccharides, which are further hydrolyzed in the periplasmic space to GlcNAc and (GlcNAc
We have presented evidence that the uptake and phosphorylation of GlcNAc, Glc, and Man in V. furnissii is mediated by the bacterial phosphoenolpyruvate:glycose phosphotransferase system (PTS)

Summary

Introduction

A b,134-linked polymer of N-acetylglucosamine (GlcNAc), is one of the most abundant organic compounds in nature Huge quantities of this highly insoluble polysaccharide are turned over annually in the aquatic biosphere, and marine bacteria such as Vibrios are major biological components of this ecologically indispensable process. Degradation of chitin by V. furnissii is initiated by chitinases that hydrolyze it to soluble oligosaccharides, which are further hydrolyzed in the periplasmic space to GlcNAc and (GlcNAc). Degradation of chitin by V. furnissii is initiated by chitinases that hydrolyze it to soluble oligosaccharides, which are further hydrolyzed in the periplasmic space to GlcNAc and (GlcNAc)2 Each of these catabolites is taken up by specific transporters and converted intracellularly to Fru-6-P, NH3, and acetate. In Escherichia coli and Salmonella typhimurium, GlcNAc is recognized and taken up by IINag, and Glc by the protein pair

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