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Research group of Ronnie Berntsson

Structural biology of type 4 secretion systems


Staff photo Ronnie Berntsson Ronnie Berntsson Associate senior lecturer (assistant professor), other position

We utilize structural biology and biochemistry/biophysics to study Type 4 Secretion Systems (T4SS), mainly from gram-positive bacteria. T4SSs transfer large defined pieces of DNA between cells, and as such are a major contributor to the horizontal gene transfer of both antibiotic resistance and virulence factors between bacteria. This can occur also between different species of bacteria. In the Berntsson lab we focus on gram-positive T4SSs, as gram-positive bacteria are responsible for the majority of the nosocomial (hospital) infections today, and as such lead to both prolonged hospitalization time and increased costs for the healthcare system. More basic knowledge is needed of these systems, both to actually understand how they work and for future development of novel antibiotics.


Cellular adhesion processes in G+ T4SSs
The adhesion process is crucial during cellular mating. A stable and direct contact needs to be made and kept stable during the entire mating process. Adhesion proteins that are part of gram-positive T4SSs bind to specific parts of the recipient cell. We study this process using both in vitro and in vivo methods to understand how the process occurs and how it is regulated, as well as studying the structure of these proteins using protein crystallography.

DNA processing in G+ T4SSs
The energetic components of the gram-positive T4SSs are responsible both for processing the substrate DNA as well as for providing the energy for the transport of the substrate over the membrane. We study the DNA interaction using various in vitro techniques in order to better understand how the proteins interact both with the DNA as well as with each other.

We are currently looking for 1-2 master students who wish to perform their master project studying gram-positive T4SSs. For more information, please contact Dr. Ronnie Berntsson.

Full publication list in PubMed