Because CGCFinder predicted no CGC for this PUL, the gene cluster depicted below contains dbCAN2 and CGC signature predictions for all genes in the PUL, instead of a predicted CGC.




23930155, J Oral Microbiol. 2013 Aug 6;5. doi: 10.3402/jom.v5i0.21285. Print 2013.

Characterization method

Western Blot,enzyme activity assay,thin layer chromatography

Genomic accession number


Nucelotide position range







Streptococcus mutans/1309

Degradation or Biosynthesis


Gene Name

Locus Tag

Protein ID

Gene Position

GenBank Contig Range

EC Number

- SMUFR_1357 AJD55828.1 0 - 2277 (-) CP007016.1:1487974-1490251 -
- SMUFR_1358 AJD55829.1 2248 - 3778 (-) CP007016.1:1490222-1491752 -
- SMUFR_1359 AJD55830.1 3892 - 4912 (-) CP007016.1:1491866-1492886 -

Cluster number


Gene name

Gene position

Gene type

Found by CGCFinder?

- 1 - 2277 (-) CAZyme: GT35 No
- 2249 - 3778 (-) CAZyme: GH77 No
- 3893 - 4912 (-) TF: DBD-Pfam|LacI,DBD-SUPERFAMILY|0036955 No




23930155, J Oral Microbiol. 2013 Aug 6;5. doi: 10.3402/jom.v5i0.21285. Print 2013.


The malQ gene is essential for starch metabolism in Streptococcus mutans.


Sato Y, Okamoto-Shibayama K, Azuma T


BACKGROUND: The malQ and glgP genes, respectively, annotated as putative 4-alpha-glucanotransferase and putative glycogen phosphorylase are located with a 29 nucleotide overlap on the Streptococcus mutans genome. We found that the glgP gene of this organism was induced with maltose, and the gene likely constituted an operon with the upstream gene malQ. This putative operon was negatively regulated with the malR gene located upstream from the malQ gene and a MalR-binding consensus sequence was found upstream of the malQ gene. S. mutans is not able to catabolize starch. However, this organism utilizes maltose degraded from starch in the presence of saliva amylase. Therefore, we hypothesized that the MalQ/GlgP system may participate in the metabolism of starch-degradation products. METHODS: A DNA fragment amplified from the malQ or glgP gene overexpressed His-tagged proteins with the plasmid pBAD/HisA. S. mutans malQ and/or glgP mutants were also constructed. Purified proteins were assayed for glucose-releasing and phosphorylase activities with appropriate buffers containing maltose, maltotriose, maltodextrin, or amylodextrin as a substrate, and were photometrically assayed with a glucose-6-phosphate dehydrogenase-NADP system. RESULTS: Purified MalQ protein released glucose from maltose and maltotriose but did not from either maltodextrin or amylodextrin. The purified GlgP protein did not exhibit a phosphorylase reaction with maltose or maltotriose but generated glucose-1-phosphate from maltodextrin and amylodextrin. However, the GlgP protein released glucose-1-phosphate from maltose and maltotriose in the presence of the MalQ protein. In addition, the MalQ enzyme activity with maltose released not only glucose but also produced maltooligosaccharides as substrates for the GlgP protein. CONCLUSION: These results suggest that the malQ gene encodes 4-alpha-glucanotransferase but not alpha-1,4-glucosidase activity. The malQ mutant could not grow in the presence of maltose as a carbon source, which suggests that the malQ gene is essential for the utilization of starch-degradation products.