Abstract
Plant phospholipases C (PLCs) that hydrolyze the phosphodiesteric linkages of the head group of phospholipids can be grouped into three major types—non-specific PLC (NPC), phosphoinositide-specific PLC (PI-PLC), and glycosylphosphatidylinositol (GPI)-PLC—according to the specificity of substrate and the cellular functions. After an overview of the main features in these plant enzymes, a case study of oat (Avena sativa) PI-PLCs isoforms is presented in this chapter to highlight insights into structure characterization of such predicted isozymes. Although oat PI-PLCs could not be purified to homogeneity due to their association with other proteins, particularly the actin cytoskeleton, the intended enzymes could be identified, analyzed, and characterized by functional proteomics, bioinformatics, and in silico approaches. In this chapter, sequence and structure analyses, as well as phylogenetic evolution of the predicted oat PI-PLCs, were reported to show the specific motifs and the main putative catalytic residues characteristics of such plant enzymes.
TopBackground
Plant PLCs are important biocatalysts that hydrolyze phospholipids (PLs) to produce diacylglycerol (DAG) as well as the respective phosphorylated head group of the substrate. They could be classified into three distinguished families of phospholipases according to substrate specificity and cellular function, i.e., glycosylphosphatidylinositol (GPI)-PLC, non-specific PLC (NPC), and phosphoinositide-specific PLC (PI-PLC). In fact, the (GPI)-PLCs hydrolyze GPI-anchors on proteins; while NPCs, also known as PC-PLCs, could catalyze common membrane PLs especially PC but other PLs such as PE; whereas PI-PLCs, also known as phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2)-PLCs, are recognized to catalyze primarily phosphoinositides (PIs) (Nakamura, Awai, & Masuda, 2005; Peters, Li, & Narasimhan, 2010, Wang, Ryu, & Wang, 2012).