Microbiology Editor's Choice: Modifying Permeability of Salmonella Microcompartments

Posted on December 2, 2019   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 ‘Engineering the PduT shell protein to modify the permeability of the 1,2-propanediol microcompartment of Salmonella’ and was chosen by Professor Dave Kelly.

Bacterial microcompartments are fascinating structures that have evolved to physically contain enzymes for specialised metabolic pathways where the intermediate components may be toxic for the cell. There is increasing interest in engineering these structures to contain new metabolic pathways for biotechnological exploitation. One challenge is to increase the permeability of the compartments to allow new or larger substrates in and products out.

This interesting paper describes work to make pores in the structures larger, by removal of an iron-sulfur cluster in the PduT shell protein of the Salmonella microcompartment for 1,2-propanediol metabolism. Guided by structural modelling, the authors used site-directed mutagenesis to remove the central Fe–S cluster of PduT, which created pores with different sizes and chemical properties. The work is a good example of protein engineering to allow expansion of the possible uses of such compartments in biotechnology. 

Engineering the PduT shell protein to modify the permeability of the 1,2-propanediol microcompartment of Salmonella

Bacterial microcompartments are huge multi-protein complexes that function as metabolic organelles. Their main purpose is to enhance difficult metabolic processes. Hence, they have potential applications in metabolic engineering for chemical production. A key feature of bacterial microcompartments is a selectively permeable protein shell. Understanding how to engineer desired permeability properties into this shell is important for optimal microcompartment design. In this report, we modify the permeability of the 1,2-propanediol microcompartment of Salmonella by site-directed mutagenesis of the PduT shell protein.

We spoke with corresponding author Thomas Bobik to find out more:

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

Iowa State University. I have been there 15 years.

What is your research area?

My main research area is bacterial genetics.

What inspired you to research this topic?

My work on microcompartments has been inspired by their uniqueness compared to other biological systems and by the fact that there is so much to learn about them.

What is the most rewarding part of your research?

The most rewarding part is working with students and postdocs and making unexpected discoveries.

What would you be doing if you weren't a scientist?

It’s hard for me to imagine not working in science in some capacity.

The full paper can be accessed on our journals platform. Editor's Choice articles published in Microbiology are free to read.