Investigating Iron-Sulfur Proteins in Infectious Diseases: A Review of Characterization Techniques

Abstract

Iron-sulfur [Fe-S] clusters, comprising coordinated iron and sulfur atoms arranged in diverse configurations, play a pivotal role in redox reactions and various biological processes. Diverse structural variants of [Fe-S] clusters exist, each possessing distinct attributes and functions. Recent discovery of [Fe-S] clusters in infectious pathogens, such as Mycobacterium tuberculosis, and in viruses, such as rotavirus, polyomavirus, hepatitis virus, mimivirus, and coronavirus, have sparked interest in them being a potential therapeutics target. Recent findings have associated these [Fe-S] cluster proteins playing a critical role in structural and host protein activity. However, for a very long time, metalloenzymes containing iron-sulfur clusters have been prone to destabilization in the presence of oxygen, which led to a delayed understanding of [Fe-S] proteins compared to other non-heme iron-containing proteins. Consequently, working with [Fe-S] proteins require specialized equipment, such as anaerobic chambers to maintain cofactor integrity, and tools like ultraviolet visible (UV-Vis) spectroscopy, mass spectrometry, X-ray crystallography, nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), Mössbauer spectroscopy and electrochemical characterization. Many of these [Fe-S] cluster proteins have been misannotated as Zinc-binding proteins when purified aerobically. Moreover, the assembly of these iron-sulfur cluster cofactors have not been fully understood since it is a multi-step assembly process. Additionally, disruptions in this assembly process have been linked to human diseases. With rapid advancements in anaerobic gloveboxes and spectroscopic techniques, characterization of these [Fe-S] cluster-containing proteins that are essential for the pathogens can open up new avenues for diagnostics and therapeutics.