title: A plant oxysterol, 28-homobrassinolide binds HMGCoA reductase catalytic cleft: stereoselective avidity affects enzyme function.
abstract: Understanding the influence of ubiquitously present plant steroids on mammalian cell biology is currently of interest. Feedback inhibition of HMGCoA reductase (HMGCR) catalytic activity in the transformation of HMG-CoA to mevalonate is a significant regulatory step in sterol biosynthetic pathway. To assess the role of dietary steroids in this biochemical transformation, the phytosteroid isoform 28-homobrassinolide (28-HB), 90 % pure, obtained from Godrej Agrovet (India) was used to determine its effect on mammalian HMG-CoA reductase. Photometric assay of pure human and select rat tissue HMGCR post 28-HB oral feed, PCR-HMGCR gene expression, and in silico docking of 28-HB and HMGCoA on HMGCR protein template were carried out. Using an oral feed regimen of pure 28-HB, we noted a decrease of 16 % in liver, 17.1 % in kidney and 9.3 % in testicular HMGCR enzyme activity, 25 % in HMGCR gene expression and 44 % in the activity of pure human HMGCR due to this plant oxysterol. In silico docking studies yielded binding metrics for 28-HB-HMGCR lower than for HMGCoA-HMGCR, indicating stronger binding of HMGCR by this ligand. 28-HB exerts differential effects on rat tissue HMGCR, down regulates liver HMGCR gene expression and significantly inhibits HMGCR activity.
authors: Department of Biochemistry & Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry, 605014, India.|Interdisciplinary Program in Life Sciences, Department of Biotechnology, Govt. of India, Pondicherry University, Puducherry, 605014, India.
authors: Victor
authors: V
authors: Mukherjee
authors: Centre for Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry, 605014, India.
authors: D
authors: D
authors: Vijayalaksmi
authors: Department of Biochemistry & Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry, 605014, India.
authors: Jagadeesh
authors: J
authors: Gulipalli
authors: Department of Biochemistry & Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry, 605014, India.
authors: R
authors: R
authors: Premalatha
authors: Department of Biochemistry & Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry, 605014, India.|Interdisciplinary Program in Life Sciences, Department of Biotechnology, Govt. of India, Pondicherry University, Puducherry, 605014, India.
authors: Shamim A
authors: SA
authors: Sufi
authors: Department of Biochemistry & Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry, 605014, India.
authors: Athithan
authors: A
authors: Velan
authors: Department of Biochemistry & Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry, 605014, India. srikumarprof@gmail.com.|Interdisciplinary Program in Life Sciences, Department of Biotechnology, Govt. of India, Pondicherry University, Puducherry, 605014, India. srikumarprof@gmail.com.
authors: Kotteazeth
authors: K
authors: Srikumar
mesh_terms: D000214:Acyl Coenzyme A / Q000378:metabolism; D000818:Animals; D002778:Cholestanones / Q000008:administration & dosage* / Q000494:pharmacology; D015536:Down-Regulation; D006801:Humans; D006903:Hydroxymethylglutaryl CoA Reductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007668:Kidney / Q000201:enzymology*; D008099:Liver / Q000201:enzymology*; D008297:Male; D008798:Mevalonic Acid / Q000378:metabolism; D062105:Molecular Docking Simulation; D051381:Rats; D013237:Stereoisomerism; D013737:Testis / Q000201:enzymology*
chemical_list: D000214:Acyl Coenzyme A; D002778:Cholestanones; C008047:3-hydroxy-3-methylglutaryl-coenzyme A; C070163:homobrassinolide; C553220:HMGCR protein, human; D006903:Hydroxymethylglutaryl CoA Reductases; D008798:Mevalonic Acid
keywords: 28-Homobrassinolide; Catalytic activity; Docking; Gene expression; HMGCR; In silico; Phytosteroid; Sterol biosynthesis