Metabolic Pathways in Mycobacterium tuberculosis that are Used for Heme Acquisition

Abstract

Since iron is an important mineral used for cellular function in Mycobacterium tuberculosis, it is crucial for it to find ways to utilize heme in human hosts in order to continue survival. Iron is not only crucial for growth in Mtb, but it also plays important roles in human cellular processes and is stored in several forms of proteins in the human body such as Lactoferrin, ferritin, transferrin, and heme. Evidence showed that the abundance of these molecules inside the human host is a potential factor for whether a pathogen will be infectious such as a highly infectious disease like Tuberculosis. The study shows that Mtb have multiple pathways and proteins that are used for acquiring iron from heme such as the DppA protein that binds substrates located inside the Dpp transporter, and pathways that are inclusive to albumin, also independent heme uptake pathways. Furthermore, two outer membrane proteins named PPE36, and PPE62 are also needed for iron acquisition. The complexity of multiple ways pathogens acquire heme can show that Mtb uses different options of heme acquisition based on the environmental factors of the human host. This may be helpful for future medicines combating Mtb, by keeping the hosts body under ideal conditions that will inhibit mTb from using these pathways thus slowing down infection or stopping colonization.