Increasing the Affinity of an O-Antigen Polysaccharide Binding Site in Shigella flexneri Bacteriophage Sf6 Tailspike Protein.

Sonja Kunstmann, Olof Engström, Marko Wehle, Göran Widmalm, Mark Santer, Stefanie Barbirz

Chemistry (Weinheim an der Bergstrasse, Germany) 2020 Jun 05

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Broad and unspecific use of antibiotics accelerates spread of resistances. Sensitive and robust pathogen detection is thus important for a more targeted application. Bacteriophages contain a large repertoire of pathogen-binding proteins. These tailspike proteins (TSP) often bind surface glycans and represent a promising design platform for specific pathogen sensors. We analysed bacteriophage Sf6 TSP that recognizes the O-polysaccharide of dysentery-causing Shigella flexneri to develop variants with increased sensitivity for sensor applications. Ligand polyrhamnose backbone conformations were obtained from 2D 1 H,1 H-trNOESY NMR utilizing methine-methine and methine-methyl correlations. They agreed well with conformations obtained from molecular dynamics (MD), validating the method for further predictions. In a set of mutants, MD predicted ligand flexibilities that were in good correlation with binding strength as confirmed on immobilized S. flexneri O-polysaccharide (PS) with surface plasmon resonance. In silico approaches combined with rapid screening on PS surfaces hence provide valuable strategies for TSP-based pathogen sensor design. © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Citation

Sonja Kunstmann, Olof Engström, Marko Wehle, Göran Widmalm, Mark Santer, Stefanie Barbirz. Increasing the Affinity of an O-Antigen Polysaccharide Binding Site in Shigella flexneri Bacteriophage Sf6 Tailspike Protein. Chemistry (Weinheim an der Bergstrasse, Germany). 2020 Jun 05;26(32):7263-7273