Acta Crystallographica Section D

Biological Crystallography

Volume 69, Part 3 (March 2013)

research papers

Acta Cryst. (2013). D69, 451-463    [ doi:10.1107/S0907444912049608 ]

GH1-family 6-P-[beta]-glucosidases from human microbiome lactic acid bacteria

K. Michalska, K. Tan, H. Li, C. Hatzos-Skintges, J. Bearden, G. Babnigg and A. Joachimiak

Abstract: In lactic acid bacteria and other bacteria, carbohydrate uptake is mostly governed by phosphoenolpyruvate-dependent phosphotransferase systems (PTSs). PTS-dependent translocation through the cell membrane is coupled with phosphorylation of the incoming sugar. After translocation through the bacterial membrane, the [beta]-glycosidic bond in 6'-­P-­[beta]-glucoside is cleaved, releasing 6-P-[beta]-glucose and the respective aglycon. This reaction is catalyzed by 6-P-[beta]-glucosidases, which belong to two glycoside hydrolase (GH) families: GH1 and GH4. Here, the high-resolution crystal structures of GH1 6-P-[beta]-glucosidases from Lactobacillus plantarum (LpPbg1) and Streptococcus mutans (SmBgl) and their complexes with ligands are reported. Both enzymes show hydrolytic activity towards 6'-P-[beta]-glucosides. The LpPbg1 structure has been determined in an apo form as well as in a complex with phosphate and a glucose molecule corresponding to the aglycon molecule. The S. mutans homolog contains a sulfate ion in the phosphate-dedicated subcavity. SmBgl was also crystallized in the presence of the reaction product 6-P-[beta]-glucose. For a mutated variant of the S. mutans enzyme (E375Q), the structure of a 6'-P-salicin complex has also been determined. The presence of natural ligands enabled the definition of the structural elements that are responsible for substrate recognition during catalysis.

PDB references: 3qom, 4gze, 3pn8, 4f66 and 4f79

Keywords: 6-P-[beta]-glucosidases; glycoside hydrolases; GH1; cellobiose; gentiobiose; salicin.

pdfdisplay filedownload file

Portable Document Format (PDF) file (1513.1 kbytes)
[ doi:10.1107/S0907444912049608/kw5053sup1.pdf ]
Supplementary material


To open or display or play some files, you may need to set your browser up to use the appropriate software. See the full list of file types for an explanation of the different file types and their related mime types and, where available links to sites from where the appropriate software may be obtained.

The download button will force most browsers to prompt for a file name to store the data on your hard disk.

Where possible, images are represented by thumbnails.

 bibliographic record in  format