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Characterization of a cytoplasmic trehalase of Escherichia coli.
J Bacteriol 1996; 178(21):6250-7JB

Abstract

Escherichia coli can synthesize trehalose in response to osmotic stress and is able to utilize trehalose as a carbon source. The pathway of trehalose utilization is different at low and high osmolarity. At high osmolarity, a periplasmic trehalase (TreA) is induced that hydrolyzes trehalose in the periplasm to glucose. Glucose is then taken up by the phosphotransferase system. At low osmolarity, trehalose is taken up by a trehalose-specific enzyme II of the phosphotransferase system as trehalose-6-phosphate and then is hydrolyzed to glucose and glucose-6-phosphate. Here we report a novel cytoplasmic trehalase that hydrolyzes trehalose to glucose. treF, the gene encoding this enzyme, was cloned under ara promoter control. The enzyme (TreF) was purified from extracts of an overexpressing strain and characterized biochemically. It is specific for trehalose exhibiting a Km of 1.9 mM and a Vmax of 54 micromol of trehalose hydrolyzed per min per mg of protein. The enzyme is monomeric, exhibits a broad pH optimum at 6.0, and shows no metal dependency. TreF has a molecular weight of 63,703 (549 amino acids) and is highly homologous to TreA. The nonidentical amino acids of TreF are more polar and more acidic than those of TreA. The expression of treF as studied by the expression of a chromosomal treF-lacZ fusion is weakly induced by high osmolarity of the medium and is partially dependent on RpoS, the stationary-phase sigma factor. Mutants producing 17-fold more TreF than does the wild type were isolated.

Authors+Show Affiliations

Department of Biology, University of Konstanz, Germany.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

8892826

Citation

Horlacher, R, et al. "Characterization of a Cytoplasmic Trehalase of Escherichia Coli." Journal of Bacteriology, vol. 178, no. 21, 1996, pp. 6250-7.
Horlacher R, Uhland K, Klein W, et al. Characterization of a cytoplasmic trehalase of Escherichia coli. J Bacteriol. 1996;178(21):6250-7.
Horlacher, R., Uhland, K., Klein, W., Ehrmann, M., & Boos, W. (1996). Characterization of a cytoplasmic trehalase of Escherichia coli. Journal of Bacteriology, 178(21), pp. 6250-7.
Horlacher R, et al. Characterization of a Cytoplasmic Trehalase of Escherichia Coli. J Bacteriol. 1996;178(21):6250-7. PubMed PMID: 8892826.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Characterization of a cytoplasmic trehalase of Escherichia coli. AU - Horlacher,R, AU - Uhland,K, AU - Klein,W, AU - Ehrmann,M, AU - Boos,W, PY - 1996/11/1/pubmed PY - 1996/11/1/medline PY - 1996/11/1/entrez SP - 6250 EP - 7 JF - Journal of bacteriology JO - J. Bacteriol. VL - 178 IS - 21 N2 - Escherichia coli can synthesize trehalose in response to osmotic stress and is able to utilize trehalose as a carbon source. The pathway of trehalose utilization is different at low and high osmolarity. At high osmolarity, a periplasmic trehalase (TreA) is induced that hydrolyzes trehalose in the periplasm to glucose. Glucose is then taken up by the phosphotransferase system. At low osmolarity, trehalose is taken up by a trehalose-specific enzyme II of the phosphotransferase system as trehalose-6-phosphate and then is hydrolyzed to glucose and glucose-6-phosphate. Here we report a novel cytoplasmic trehalase that hydrolyzes trehalose to glucose. treF, the gene encoding this enzyme, was cloned under ara promoter control. The enzyme (TreF) was purified from extracts of an overexpressing strain and characterized biochemically. It is specific for trehalose exhibiting a Km of 1.9 mM and a Vmax of 54 micromol of trehalose hydrolyzed per min per mg of protein. The enzyme is monomeric, exhibits a broad pH optimum at 6.0, and shows no metal dependency. TreF has a molecular weight of 63,703 (549 amino acids) and is highly homologous to TreA. The nonidentical amino acids of TreF are more polar and more acidic than those of TreA. The expression of treF as studied by the expression of a chromosomal treF-lacZ fusion is weakly induced by high osmolarity of the medium and is partially dependent on RpoS, the stationary-phase sigma factor. Mutants producing 17-fold more TreF than does the wild type were isolated. SN - 0021-9193 UR - https://www.unboundmedicine.com/medline/citation/8892826/Characterization_of_a_cytoplasmic_trehalase_of_Escherichia_coli_ L2 - http://jb.asm.org/cgi/pmidlookup?view=long&pmid=8892826 DB - PRIME DP - Unbound Medicine ER -