In silico modification of the isopentenyl pyrophosphate isomerase 1 enzyme from Stevia rebaudiana useful for metabolic regulation study

Abstract

Stevia rebaudiana is a plant commonly used as a source of natural sweeteners obtained from its leaves and stems that give the characteristic intense sweetness due to the accumulation of compounds known as steviol glycosides (SGs). These compounds are used as a substitute for sucrose and offer health benefits due to its low content in calories, added to antihypertensive and anti-cancer properties, etc. The SGs are produced via the 2-C-methyl-D-erythritol 4-phosphate pathway using isoprenoids as precursors. This route is specific to chloroplasts and currently it is known relatively little about its regulation and the mechanisms that direct metabolic fluxes in convergent points of biosynthetic routes, one of those important points of regulation is the catalyzed by the enzyme isopentenyl pyrophosphate isomerase 1 (IPI1). The present study reports the modification and in silico design of the messenger RNA corresponding to IPI1, through the change of a methionine by leucine at the position 141 (M141L) of the sequence reported for S. rebaudiana. In addition, the nucleotide sequence codonic usage was optimized to improve its expression efficiency. Finally, homology modelling analyses were performed to the sequence to obtain a putative model of the modified enzyme and study its interaction with ligands and substrate. This modified sequence will be useful for studying the metabolic regulation that is exerted on the production of GEs in S. rebaudiana.