Database for Polyphenol Utilized Proteins from gut microbiota

Subfamily Sequences

Literature Information

Title Biotransformation of phloretin by amylosucrase yields three novel dihydrochalcone glucosides
Author Heike Overwin, Victor Wray, Bernd Hofer
DOI 10.1016/j.jbiotec.2015.07.002
Abstract Glycosylation is one of the most important tailoring reactions for natural products. It typically exerts profound direct or indirect effects on their biological activity. The dihydrochalcone phloretin and its known sugar derivatives, particularly phlori(d)zin, have been shown to influence various cellular processes. We found that a non-Leloir glycosyltransferase, amylosucrase from Neisseria polysaccharea, is an excellent catalyst for the stereospecific glucosylation of phloretin at the 4’ position. Three novel phloretin derivatives were obtained, the first ones in which the sugar-aglycone bond possesses the configuration. A first biological characterization in a cell viability assay showed that each sugar attachment reduced the compound toxicity approximately two-fold.

Experimental results

  • Enzyme

Uniprot ID: Q9ZEU2

Protein: Amylosucrase

Organism: Neisseria polysaccharea

Length: 636 AA

Taxonomic identifier: 489 [NCBI]

  • Pfam
Source Domain Start End E-value (Domain) Coverage
Pfam-A Alpha-amylase 118 336 3.6e-34 0.629

Program: hmmscan

Version: 3.1b2 (February 2015)

Method: hmmscan --domtblout hmmscan.tbl --noali -E 1e-5 pfam query.fa

Date: Mon Jul 20 14:32:16 2020




Alpha amylase is classified as family 13 of the glycosyl hydrolases. The structure is an 8 stranded alpha/beta barrel containing the active site, interrupted by a ~70 a.a. calcium-binding domain protruding between beta strand 3 and alpha helix 3, and a carboxyl-terminal Greek key beta-barrel domain.


O-Glycosyl hydrolases (3.2.1.) are a widespread group of enzymes that hydrolyse the glycosidic bond between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycosyl hydrolases, based on sequence similarity, has led to the definition of 85 different families12. This classification is available on the CAZy (CArbohydrate-Active EnZymes) website.

Enzymes containing this domain, such as alpha-amylase, belong to family 13 (GH13) of the glycosyl hydrolases. The maltogenic alpha-amylase is an enzyme which catalyses hydrolysis of (1-4) -alpha-D-glucosidic linkages in polysaccharides so as to remove successive alpha-maltose residues from the non-reducing ends of the chains in the conversion of starch to maltose. Other enzymes include neopullulanase, which hydrolyses pullulan to panose, and cyclomaltodextrinase, which hydrolyses cyclodextrins.

This entry represents the catalytic domain found in several protein members of this family. It has a structure consisting of an 8 stranded alpha/beta barrel that contains the active site, interrupted by a ~70 amino acid calcium-binding domain protruding between beta strand 3 and alpha helix 3, and a carboxyl-terminal Greek key beta-barrel domain3.

Information is taken from Pfam and InterPro web site.

  • Reaction

phloretin ⇒ Phlo-A1 + Phlo-A2 + Phlo-A3


  1. Henrissat B, Callebaut I, Fabrega S, et al. Conserved catalytic machinery and the prediction of a common fold for several families of glycosyl hydrolases[J]. Proceedings of the National Academy of Sciences, 1995, 92(15): 7090-7094. 

  2. Davies G, Henrissat B. Structures and mechanisms of glycosyl hydrolases[J]. Structure, 1995, 3(9): 853-859. 

  3. Abe A, Yoshida H, Tonozuka T, et al. Complexes of Thermoactinomyces vulgaris R‐47 α‐amylase 1 and pullulan modeloligossacharides provide new insight into the mechanism for recognizing substrates with α‐(1, 6) glycosidic linkages[J]. The FEBS journal, 2005, 272(23): 6145-6153. 

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