Open AccessScrB (Cg2927) is a sucrose‐6‐phosphate hydrolase essential for sucrose utilization by Corynebacterium glutamicum
Author(s) -
Engels Verena,
Georgi Tobias,
Wendisch Volker F.
Publication year - 2008
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2008.01370.x
Subject(s) - sucrose , corynebacterium glutamicum , fructose , biochemistry , hydrolase , sucrose phosphate synthase , pep group translocation , sugar phosphates , phosphate , invertase , chemistry , biology , hydrolysis , mutant , enzyme , sucrose synthase , gene
Corynebacterium glutamicum can grow on a variety of carbohydrates from which glucose, fructose and sucrose are taken up and phosphorylated by the phosphoenolpyruvate‐dependent phosphotransferase system (PTS). Here, we show that cg2927 ( scrB ) encodes sucrose‐6‐phosphate hydrolase. The purified His‐tagged protein hydrolyzed sucrose‐6‐phosphate and sucrose, but not sucrose‐6′‐phosphate. The K m value for sucrose was 190 mM while the K m for sucrose‐6‐phosphate was much lower, 0.04 mM. Sucrose‐6‐phosphate hydrolase activity was stimulated by MgSO 4 and fructose‐6‐phosphate and was inhibited by MnCl 2 , CaCl 2 , CuSO 4 and ZnSO 4 . A scrB deletion mutant could not grow on sucrose as the sole carbon source. In addition, growth in the absence of scrB was severely decreased when sucrose was present in addition to glucose, fructose or acetate, suggesting that higher intracellular concentrations of sucrose‐6‐phosphate are toxic. Transcriptional start sites in the cg2929‐cg2928 ‐ scrB‐ptsS locus could be revealed upstream of cg2929 and upstream of the sucrose‐specific PTS gene ptsS . Of these, only ptsS showed increased expression when grown in the presence of sucrose, which was due to control by the transcriptional regulator SugR. The sucrose‐6‐phosphate hydrolase activity, however, was increased two‐ to threefold during growth in fructose‐ or sucrose‐containing media, regardless of the presence or absence of SugR.