In Silico Structural Determination of GPAT Enzyme from Ostreococcus Lucimarinus for Biotechnological Application of Microalgal Biofuel Production

ABSTRACT

Glycerol-3-phosphate acyltransferase (GPAT) is an enzyme in the triacylglycerol (TAG) biosynthetic pathway that catalyses the conversion of glycerol-3-phosphate to lysophosphatidic acid. Targeting key enzymes involved in TAG pathway is considered to be a powerful strategy for augmented lipid accumulation in microorganisms. In the present study three-dimensional structure of the marine microalgae, Ostreococcus lucimarinus GPAT protein was developed based on the crystal structure of Cucurbita moschata GPAT protein. Besides, several structure validation tools were employed to confirm the reliability of the developed model. The predicted and validated model reveals the tertiary structure of GPAT monomer comprising of two domains, the smaller domain I, which folds into a four helix bundle, and the larger domain II, which is constructed from alternating α/β secondary structural elements that give rise to 9-stranded β sheet flanked by 11α helices. Critical structural analysis of the developed model reveals the presence of H(X) ₄D motif; the latter being, a consensus sequence conserved amongst many glycerolipid acyltransferase. The detected cluster of positively charged residues H¹⁸⁹, K²⁴³, H²⁴⁴, R²⁸⁵ and R²⁸⁷ in the model could be conjectured to be important in glycerol-3-phosphate recognition. The structural insight obtained from this in silico study may provide useful clues to further advanced biotechnological studies of strategic site-specific genetic and metabolic engineering of microalgae for enhanced biofuel production.

Keywords:

• homology modeling
• molecular dynamics
• GPAT
• Ostreococcus lucimarinus
• microalgae
• biofuel
• TAG pathway