Detailed knowledge of the toxins, including their three-dimensional structure, is essential here. Recently, a NMR protocol was established for hLTB (human LT B-subunit) and the complete backbone was successfully assigned (Ref. 3 below). These results, and recent crystallization studies (Refs. 2 and 4) are the basis for further interaction studies between hLTB and different ligands. In particular, we are interested to study the toxin interactions with LPS and intracellular chaperones.
This work will allow insights into the underlying mechanism and may serve as basis for future drug or vaccine development.
Fig. 1. Hybrid toxin B-pentamer with blood group A analog A-pentasaccharide (blue) and primary receptor GM1 (green) bound. Superimposition of PDB entries 3CHB and 3EFX.
Aim: Depending on the project, the Master’s student will be focusing on toxin delivery mechanisms to human intestinal cells or on the intracellular activation mechanism of the toxins. With guidance from supervising PhD students, the Master’s students will express recombinant toxin, purify it by protein purification methods, and investigate binding to ligands by X-ray crystallography or NMR. The aim of all projects is to get a better understanding of the underlying molecular interactions, and how they can be exploited to fight disease (see Ref. 2 below).
Methods: Standard DNA techniques (PCR, mutagenesis), protein expression and purification, binding studies, crystallization, NMR and data analysis.
Supervisors: Ute Krengel (Professor), Joel B. Heim (PhD student) (for one of the projects also Per Eugen Kristiansen and Daniel Haltem)
Contact info: Department of Chemistry (room VU74)
ute.krengel@kjemi.uio.no, j.b.heim@kjemi.uio.no
http://www.mn.uio.no/kjemi/english/research/projects/bacterial-toxins
Additional information: The group currently consists of 3 PhD students and 1 Postdoc. The NMR-related project will be in collaboration with Per Eugen Kristiansen at IBV and PhD student Daniel Hatlem.
Please feel welcome to contact us!
Selected publications:
1) Heggelund et al. (2017) Histo-blood group antigens as mediators of infections. Curr Opin Struct Biol. 44:190-200.
2) Heggelund et al. (2017) Towards new cholera prophylactics and treatment: Crystal structures of bacterial enterotoxins in complex with GM1 mimics. Sci Rep. 7:2326.
3) Hatlem et al. (2017) 1H, 13C, 15N backbone assignment of the human heat-labile enterotoxin B-pentamer and chemical shift mapping of neolactotetraose binding. Biomol NMR Assign. 11:99-104.
4) Heggelund et al. (2016) High-Resolution Crystal Structures Elucidate the Molecular Basis of Cholera Blood Group Dependence. PLoS Pathog. 12:e1005567.
5) R?ntgenkjemiker l?ser kolerag?te, 澳门葡京手机版app下载smagasinet Apollon (2012), 3, 26-29.
6) Heggelund, Bj?rnestad & Krengel (2015). Vibrio cholerae and Escherichia coli heat-labile enterotoxins and beyond. In The comprehensive sourcebook of bacterial protein toxins (eds Alouf & Popoff). Elsevier. ISBN 978-0-12-800188-2.