Elucidating the Molecular Anatomy of Acetyl-CoA Carboxylase in Brassica Rapa for Evolving Climate-Resilient Interventions to Minimize Carbon Footprints

Abstract

Climate change is an emerging threat to food & nutritional security. It adversely affects crop production by altering the gene expression patterns of genes encoding for growth, development, and crop yield. Further, carbon emissions during crop production processes coupled with rapid urbanization & industrialization, and deforestation drive aggravate the climate change problem. Therefore, innovative adaptive measures must be developed in terms of climate-resilient interventions for enhancing productivity by minimizing expanding carbon footprints. In this investigation, we developed molecular models of different components (biotin carboxylase (BC), biotin carboxyl carrier protein (BCCP), and carboxyl transferase (CT)) of an important enzyme acetyl-CoA carboxylase (ACC) of Brassica rapa which play a vital role in carbon sequestration in fatty acids and regulation of fatty acid metabolism. We successfully built molecular models of BC, BCCP, CT-α, and CT-β having sufficient degree of reliability and stereochemical quality scores as obtained from the structure validation using PROCHECK, ProSA, Verify3D, and ERRAT. Further, we did a set of molecular docking studies with models of BC, BCCP, and CT (CT-α, CT-β) with their ligands (ATP, biotin, acetyl coenzyme-A) to know the active site residues involved in catalysis reaction using AutoDock-Vina. Our findings on the molecular architecture of different components of ACC in Brassica rapa and ligand binding sites of component proteins from the molecular docking studies will help in two different ways. Firstly, structural information of model would facilitate designing of site-directed mutagenesis based functional genomic studies for comprehending the putative role of ACC in fatty acid biosynthesis, regulation of ACC by light & other molecular players reported in other species such as CTI & PII proteins. Further, functional haplotype markers can be designed using active site information of ACC in Brassica rapa to improve oil content by amalgamating desired set of available genomic variations present in different cultivars and landraces using the molecular breeding programme and genome editing tools. Such findings are potential drivers for minimizing carbon footprints by sequestering carbon in carbon skeletons of fatty acids in minimal input requiring oil-producing crop plants (Brassica rapa).