Microbiology Editor’s Choice: mycobacterial growth in iron limiting conditions

Posted on April 1, 2020   by Microbiology Society

Each month, a manuscript published in our flagship journal Microbiology  is chosen by a member of the Editorial Board. This month, the paper is titled “SufT is required for growth of Mycobacterium smegmatis under iron-limiting conditions” and it was chosen by Professor Jörg Stülke.

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Iron is a growth limiting factor for most pathogenic bacteria, and the bacteria have developed elaborate strategies to acquire iron from the host, whereas the prevention of bacterial iron acquisition is one of the major factors in innate immunity. For the generation and assembly of iron-sulphur clusters as well as for their insertion into protein, so-called Suf proteins are required. This new study by Tsaone Tamuhla and colleagues is published in the current issue of Microbiology, and addresses the role of the SufT protein in Mycobacterium smegmatis.
While the protein is dispensable under standard growth conditions, it is required under conditions of iron limitation suggesting that SufT may facilitate the maturation of iron-sulphur clusters if iron becomes growth-limiting. Since the Suf system is the only way to assemble iron-sulphur clusters also in important pathogens such as Mycobacterium tuberculosis and Mycobacterium leprae, the results of the current study indicate that SufT might be very important for the virulence of these bacteria that are faced with iron limitation when they enter the human host.

SufT is required for growth of Mycobacterium smegmatis under iron limiting conditions

Mycobacterial infections have an important impact on human health. Most notably, infection with Mycobacterium tuberculosis results in approximately 1.5 million deaths each year.

Iron-sulphur clusters are molecules made up of atoms of iron and sulphur, which are required in several critical cellular processes. In mycobacteria, the process by which iron-sulphur clusters are synthesized is poorly understood. This study investigated the protein SufT, which is involved in iron-sulphur cluster synthesis in the bacteria Mycobacterium smegmatis. We demonstrated that SufT is required by M. smegmatis to grow when iron is limited. This finding is significant since mycobacteria are thought to experience iron limitation during infection.

We spoke with the corresponding author Dr Monique Williams to find out more:

What is your institution and how long have you been there?

This work was conducted at Stellenbosch University, where I was based for nine years. I recently moved to the Division of Molecular Biology and Human Genetics at the University of Cape Town.

What is your research area? 

Mycobacterial physiology and iron-sulphur cluster biogenesis

What inspired you to research this topic?
Our research is aimed at identifying and understanding pathways/proteins that are required by mycobacteria during infection, with the goal of using this knowledge in drug development and diagnostics.
What is the most rewarding part of your research?
As a mentor, it is rewarding to see students excited about their research and results.
What would you be doing if you weren't a scientist?

I am passionate about education, so I would probably be involved in teaching in some way.

Follow Dr Williams’ co-authors Tsaone Tamuhla and Danicke Willemse on Twitter.

Visit our journals platform to access the full paper. Editor’s Choice articles published in Microbiology are free to read.