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Biosynthesis of novel 7,8‐dihydroxyflavone glycoside derivatives and in silico study of their effects on BACE1 inhibition
Author(s) -
Pandey Ramesh Prasad,
Parajuli Prakash,
Pokhrel Anaya Raj,
Sohng Jae Kyung
Publication year - 2017
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1002/bab.1570
Subject(s) - chemistry , bacillus licheniformis , glucoside , enzyme , biochemistry , glycoside , bioconversion , high performance liquid chromatography , stereochemistry , escherichia coli , biosynthesis , fermentation , chromatography , bacteria , biology , gene , medicine , genetics , alternative medicine , pathology , bacillus subtilis
7,8‐Dihydroxyflavone (7,8‐DHF) has been conjugated with glucose moiety to produce glucoside derivatives. Three analogues of 7,8‐DHF (7‐ O ‐ β ‐ d ‐glucosyl‐8‐hydroxyflavone, 7‐hydroxy‐8‐ O ‐ β ‐ d ‐glucosyl flavone, and 7,8‐di‐ O ‐ β ‐ d ‐glucosylflavone) have been successfully produced from in vitro reaction using glycosyltransferase of Bacillus licheniformis . Production of these 7,8‐DHF derivatives were shifted to cheaper and easier approach in this study by using engineered Escherichia coli BL21 (DE3) Δ pgi Δ zwf Δ ushA cells in which the flow of glucose‐6‐phospahte toward glycolysis and pentose phosphate pathway and hydrolysis of UDP‐ α ‐ d ‐glucose were blocked while directing the carbon flux toward UDP‐ α ‐ d ‐glucose by overexpressing UDP‐ α ‐ d ‐glucose pathway genes. Supplementation of 300 μM of 7,8‐DHF to the culture resulted in production of 171 μM of 7‐ O ‐ β ‐ d ‐glucosyl‐8‐hydroxyflavone, 68 μM of 7‐hydroxy‐8‐ O ‐ β ‐ d ‐glucoxyflavone, and 55 μM of 7,8‐di‐ O ‐ β ‐ d ‐glucoxyflavone in laboratory‐scale 3‐L fermentor, representing 98% bioconversion of initially fed substrate to respective glucoside derivatives within 48 H. These products were characterized by high‐performance liquid chromatography‐photodiode array (HPLC‐PDA), HPLC‐PDA‐quadruple time of flight‐electron spray ionization mass spectrometry, and nuclear magnetic resonance analyses. These newly synthesized derivatives were found to be able to interact with amino acids of active site of human β ‐site amyloid precursor protein cleaving β ‐site amyloid precursor protein cleaving enzyme 1 (BACE1) β ‐secretase enzyme in in silico studies, thus displaying possible application in cure of Alzheimer's disease.