Substrate Selectivities of GH78 α-L-Rhamnosidases from Human Gut Bacteria on Dietary Flavonoid Glycosides

α-L-rhamnosidases play a key role in the metabolism and biodegradation of dietary flavonoid glycosides. We have developed a novel microplate spectrophotometric method to rapidly evaluate the conversion rates and substrate selectivities of mesophilic α-L-rhamnosidases towards citrus flavanone diglyco...

Full description

Saved in:
Bibliographic Details
Main Authors: Bin-Chun Li, Bingbing Wu, Xueting Hou, Guo-Bin Ding
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Molecules
Subjects:
Online Access:https://www.mdpi.com/1420-3049/30/5/980
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850030302927257600
author Bin-Chun Li
Bingbing Wu
Xueting Hou
Guo-Bin Ding
author_facet Bin-Chun Li
Bingbing Wu
Xueting Hou
Guo-Bin Ding
author_sort Bin-Chun Li
collection DOAJ
description α-L-rhamnosidases play a key role in the metabolism and biodegradation of dietary flavonoid glycosides. We have developed a novel microplate spectrophotometric method to rapidly evaluate the conversion rates and substrate selectivities of mesophilic α-L-rhamnosidases towards citrus flavanone diglycosides by combining with a high-active and thermophilic β-D-glucosidase based on UV-visible spectral differences between citrus flavanone diglycosides and the corresponding aglycones under alkaline conditions. Furthermore, catalytic activities and enzyme kinetics of four α-L-rhamnosidases from human gut bacteria on various dietary flavonoid glycosides with different glycosidic bonds from various subclasses have been explored by HPLC. The α-L-rhamnosidase BtRha78A specifically removed the rhamnose group from the flavones, flavanones and flavonols diglycosides with the α-1,6 glycosidic bonds. Moreover, BtRha78A displayed higher catalytic activities on the rutinose group at 7-OH of the aglycones than at 3-OH. HFM-RhaA preferred to catalyze the flavones, flavanones and dihydrochalcones diglycosides with the α-1,2 glycosidic linkages at the 7-OH. However, this enzyme also showed high catalytic activity on the flavonol diglycoside rutin with the α-1,6 glycosidic bonds at the 3-OH. HFM-RhaC exhibited certain hydrolytic abilities towards all flavonoid diglycosides, and displayed higher activities on the flavonoid diglycosides with the α-1,6 glycosidic bonds. HFM-Rha78 weakly hydrolyzed the flavones, flavanones and dihydrochalcones diglycosides with the α-1,2 glycosidic bonds, and the flavonols diglycosides with α-1,6 glycosidic bonds. All four α-L-rhamnosidases from human gut bacteria did not exhibit catalytic activity towards the flavonoid glycosides with the α-1 glycosidic bonds. It was revealed that the α-L-rhamnosidases from human gut bacteria possessed diverse substrate selectivity on dietary flavonoid diglycosides. The structural basis for the specificity of BtRha78A on the flavonoid diglycosides with α-1,6 glycosidic bonds and the preference of HFM-RhaA on the flavonoid diglycosides with α-1,2 glycosidic bonds have been analyzed by molecular docking.
format Article
id doaj-art-c92de5e1602a48cc93b349167ba6bcef
institution DOAJ
issn 1420-3049
language English
publishDate 2025-02-01
publisher MDPI AG
record_format Article
series Molecules
spelling doaj-art-c92de5e1602a48cc93b349167ba6bcef2025-08-20T02:59:15ZengMDPI AGMolecules1420-30492025-02-0130598010.3390/molecules30050980Substrate Selectivities of GH78 α-L-Rhamnosidases from Human Gut Bacteria on Dietary Flavonoid GlycosidesBin-Chun Li0Bingbing Wu1Xueting Hou2Guo-Bin Ding3Institute of Biotechnology, Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, Taiyuan 030006, ChinaInstitute of Biotechnology, Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, Taiyuan 030006, ChinaInstitute of Biotechnology, Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, Taiyuan 030006, ChinaInstitute of Biotechnology, Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, Taiyuan 030006, Chinaα-L-rhamnosidases play a key role in the metabolism and biodegradation of dietary flavonoid glycosides. We have developed a novel microplate spectrophotometric method to rapidly evaluate the conversion rates and substrate selectivities of mesophilic α-L-rhamnosidases towards citrus flavanone diglycosides by combining with a high-active and thermophilic β-D-glucosidase based on UV-visible spectral differences between citrus flavanone diglycosides and the corresponding aglycones under alkaline conditions. Furthermore, catalytic activities and enzyme kinetics of four α-L-rhamnosidases from human gut bacteria on various dietary flavonoid glycosides with different glycosidic bonds from various subclasses have been explored by HPLC. The α-L-rhamnosidase BtRha78A specifically removed the rhamnose group from the flavones, flavanones and flavonols diglycosides with the α-1,6 glycosidic bonds. Moreover, BtRha78A displayed higher catalytic activities on the rutinose group at 7-OH of the aglycones than at 3-OH. HFM-RhaA preferred to catalyze the flavones, flavanones and dihydrochalcones diglycosides with the α-1,2 glycosidic linkages at the 7-OH. However, this enzyme also showed high catalytic activity on the flavonol diglycoside rutin with the α-1,6 glycosidic bonds at the 3-OH. HFM-RhaC exhibited certain hydrolytic abilities towards all flavonoid diglycosides, and displayed higher activities on the flavonoid diglycosides with the α-1,6 glycosidic bonds. HFM-Rha78 weakly hydrolyzed the flavones, flavanones and dihydrochalcones diglycosides with the α-1,2 glycosidic bonds, and the flavonols diglycosides with α-1,6 glycosidic bonds. All four α-L-rhamnosidases from human gut bacteria did not exhibit catalytic activity towards the flavonoid glycosides with the α-1 glycosidic bonds. It was revealed that the α-L-rhamnosidases from human gut bacteria possessed diverse substrate selectivity on dietary flavonoid diglycosides. The structural basis for the specificity of BtRha78A on the flavonoid diglycosides with α-1,6 glycosidic bonds and the preference of HFM-RhaA on the flavonoid diglycosides with α-1,2 glycosidic bonds have been analyzed by molecular docking.https://www.mdpi.com/1420-3049/30/5/980substrate selectivity?-L-rhamnosidasedietary flavonoid glycosideshuman gut bacteria
spellingShingle Bin-Chun Li
Bingbing Wu
Xueting Hou
Guo-Bin Ding
Substrate Selectivities of GH78 α-L-Rhamnosidases from Human Gut Bacteria on Dietary Flavonoid Glycosides
Molecules
substrate selectivity
?-L-rhamnosidase
dietary flavonoid glycosides
human gut bacteria
title Substrate Selectivities of GH78 α-L-Rhamnosidases from Human Gut Bacteria on Dietary Flavonoid Glycosides
title_full Substrate Selectivities of GH78 α-L-Rhamnosidases from Human Gut Bacteria on Dietary Flavonoid Glycosides
title_fullStr Substrate Selectivities of GH78 α-L-Rhamnosidases from Human Gut Bacteria on Dietary Flavonoid Glycosides
title_full_unstemmed Substrate Selectivities of GH78 α-L-Rhamnosidases from Human Gut Bacteria on Dietary Flavonoid Glycosides
title_short Substrate Selectivities of GH78 α-L-Rhamnosidases from Human Gut Bacteria on Dietary Flavonoid Glycosides
title_sort substrate selectivities of gh78 α l rhamnosidases from human gut bacteria on dietary flavonoid glycosides
topic substrate selectivity
?-L-rhamnosidase
dietary flavonoid glycosides
human gut bacteria
url https://www.mdpi.com/1420-3049/30/5/980
work_keys_str_mv AT binchunli substrateselectivitiesofgh78alrhamnosidasesfromhumangutbacteriaondietaryflavonoidglycosides
AT bingbingwu substrateselectivitiesofgh78alrhamnosidasesfromhumangutbacteriaondietaryflavonoidglycosides
AT xuetinghou substrateselectivitiesofgh78alrhamnosidasesfromhumangutbacteriaondietaryflavonoidglycosides
AT guobinding substrateselectivitiesofgh78alrhamnosidasesfromhumangutbacteriaondietaryflavonoidglycosides