Abstract
The Erythrocyte Binding Ligand (EBL) is an important protein of Plasmodium sp. required by the parasite for successful invasion into the red blood cells causing malaria. EBL is a potential anti-malarial drug target. Despite its importance only a portion of its structure i.e., Duffy Binding Domain (DBD), is solved. Thus, the remaining regions necessitate attention and probing. In this study, it is reported that EBL protein consists of massive unstructured regions in between two compact structured portions, viz., the DBD and a C-terminus trans-membrane domain as predicted from our bioinformatics studies on Plasmodium vivax. Our study reveals that its major parts of the unstructured portions consist of Intrinsically Disordered Regions (IDR). Since IDRs have high rates of plasticity, the hypothesis is that it allows large molecular movements between the two structured portions of EBL helping the DBD to find its target receptor. Here, a schematic of the overall structural organization of EBL and its functional model is proposed. Thus, our study signifies possible importance of hitherto unexplored ‘disordered’-ness in EBLs in mediating pathogenesis in Plasmodium sp.
Key words: Plasmodium, Malaria, EBL, EBA, IDP, IDR, drug target, plasticity, evolution.