Targeting FK506 binding proteins to fight malarial and bacterial infections: current advances and future perspectives.

There is an urgent need for the design and development of new and selective drugs for the treatment of malaria and bacterial infections as these pathogens are developing resistance to presently available therapies. Malaria is a life threatening disease in many countries and responsible for almost one million deaths annually. In particular, drug-resistant malarial parasites are hindering effective control of malaria and prompting to find novel druggable targets and develop compounds with mechanism of action different from the conventional drugs. In this quest, efforts were made to determine three-dimensional structures of Plasmodium falciparum and Plasmodium vivax FK506 binding proteins which bind the macrolides (FK506 and rapamycin) and also demonstrate peptidylprolyl cis-trans isomerase activity in a similar manner as human FKBP12. Previous studies revealed that the immunosuppressive drug FK506 exhibits potential anti-malarial activity by binding FK506 binding domains (FKBD). This review focuses on three different types of FK506 binding proteins/domains in pathogens, their structural characteristics and biological roles. Binding ability of these proteins with the macrolides has opened new possibilities to develop selective inhibitors for these novel targets to combat the life threatening infections.