Ronnie Berntsson - Assistant Professor

Structural biology of type 4 secretion systems

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.

Groups members:
Dr. Andreas Schmitt, postdoctoral fellow
Dr. Saima Rehman, postdoctoral fellow
Lena Lassinantti, PhD Student

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.


For a full list of publications, please see:

Selected publications

Zhang S1, Berntsson RP-A1, Tepp WH, Tao L, Johnson EA, Stenmark P and Dong M. Structural basis for the unique ganglioside and cell membrane binding mechanism of botulinum neurotoxin DC. Nature Communications doi:10.1038/s41467-017-01534-z

Hamark C1, Berntsson RP-A1, Masuyer G, Henriksson L, Gustafsson R, Stenmark P, and Widmalm G. (2017) Glycans Confer Specificity to the Recognition of Ganglioside Receptors by Botulinum Neurotoxin A. Journal of American Chemical Society. doi: 10.1021/jacs.6b09534

Dunny G. and Berntsson RP-A1. (2016) Enterococcal sex pheromones: evolutionary pathways to complex two-signal systems. Journal of Bacteriology 198: 1556-1562

Berntsson RP-A1, Odegrip R1, Sehlen W, Skaar K, Svensson LM, Massad T, Högbom M, Haggård-Ljungquist E, Stenmark P (2014). Structural insight into DNA binding and oligomerization of the multifunctional Cox protein of bacteriophage P2. Nucleic Acids Research 42: 2725-2735

Berntsson RP-A, Peng L, Dong M, Stenmark P (2013) Structure of dual receptor binding to Botulinum neurotoxin B. Nature Communications. doi: 10.1038/ncomms3058

Berntsson RP-A1, Beek ter J1, Majsnerowska M1, Duurkens RH, Puri P, Poolman B, Slotboom D-J (2012) Structural divergence of paralogous S components from ECF-type ABC transporters. Proceedings of the National Academy of Sciences U S A 109: 13990-13995.

Klepsch MM, Kovermann M, Löw C, Balbach J, Permentier HP, Fusetti F, Gier de JW, Slotboom D-J, Berntsson RP-A (2011) Escherichia coli Peptide Binding Protein OppA Has a Preference for Positively Charged Peptides. Journal of Molecular Biology 414: 75–85

Berntsson RP-A, Doeven MK, Fusetti F, Duurkens RH, Sengupta D, Marrink S-J, Thunnissen A-MWH, Poolman B, Slotboom D-J (2009) The structural basis for peptide selection by the transport receptor OppA. EMBO Journal 28: 1332–1340

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Umeå University
Medical Biochemistry and Biophysics
SE-901 87 Umeå, Sweden 

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