Open AccessNatural product juglone targets three key enzymes from Helicobacter pylori : inhibition assay with crystal structure characterization 1
Author(s) -
KONG Yunhua,
ZHANG Liang,
YANG Zhengyi,
HAN Cong,
HU Lihong,
JIANG Hualiang,
SHEN Xu
Publication year - 2008
Publication title -
acta pharmacologica sinica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.514
H-Index - 90
eISSN - 1745-7254
pISSN - 1671-4083
DOI - 10.1111/j.1745-7254.2008.00808.x
Subject(s) - juglone , uncompetitive inhibitor , non competitive inhibition , chemistry , enzyme , dehydratase , mixed inhibition , stereochemistry , ic50 , biochemistry , in vitro
Aim: To investigate the inhibition features of the natural product juglone (5‐hydroxy‐1,4‐naphthoquinone) against the three key enzymes from Helicobacter pylori (cystathionine γ‐synthase [HpCGS], malonyl‐CoA:acyl carrier protein transacylase [HpFabD], and β‐hydroxyacyl‐ACP dehydratase [HpFabZ]). Methods: An enzyme inhibition assay against HpCGS was carried out by using a continuous coupled spectrophotometric assay approach. The inhibition assay of HpFabD was performed based on the α‐ketoglutarate dehydrogenase‐coupled system, while the inhibition assay for HpFabZ was monitored by detecting the decrease in absorbance at 260 nm with crotonoyl‐CoA conversion to β‐hydroxybutyryl‐CoA. The juglone/FabZ complex crystal was obtained by soaking juglone into the HpFabZ crystal, and the X‐ray crystal structure of the complex was analyzed by molecular replacement approach. Results: Juglone was shown to potently inhibit HpCGS, HpFabD, and HpFabZ with the half maximal inhibitory concentration IC 50 values of 7.0±0.7, 20±1, and 30±4 μmol/L, respectively. An inhibition‐type study indicated that juglone was a non‐competitive inhibitor of HpCGS against O ‐succinyl‐ L ‐homoserine ( K i =α K i =24 μmol/L), an uncompetitive inhibitor of HpFabD against malonyl‐CoA (α K i =7.4 μmol/L), and a competitive inhibitor of HpFabZ against crotonoyl‐CoA ( K i =6.8 μmol/L). Moreover, the crystal structure of the HpFabZ/juglone complex further revealed the essential binding pattern of juglone against HpFabZ at the atomic level. Conclusion: HpCGS, HpFabD, and HpFabZ are potential targets of juglone.