C2 domain present in the putative elicitor-responsive gene
In plants elicitor-responsive proteins are triggered in response to specific elicitor molecules such as glycolproteins, peptides, carbohydrates and lipids. A host of defensive responses are also triggered resulting in localized cell death. Antimicrobial secondary metabolites, such as phytoalexins, or defense-related proteins, including pathogenesis-related (PR) proteins are also produced. There is a single C2 domain present here. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. Members have a type-II topology.