Molecular mechanism of extreme mechanostability in a pathogen adhesin

Abstract

How a pathogen holds on to its host Staphylococcus epidermidis and Staphylococcus aureus are pathogens that can form biofilms on implants and medical devices. Central to biofilm formation is a very tight interaction between microbial surface proteins called adhesins and components of the extracellular matrix of the host. Milles et al. used atomic force microscopy-based single-molecule force spectroscopy combined with steered molecular dynamics to explore how the bond between staphylococcal adhesin SdrG and its target fibrinogen peptide can withstand forces greater than 2 nanonewtons (see the Perspective by Herman-Bausier and Dufrêne). The peptide is confined in a coiled geometry in a deep and rigid pocket through hydrogen bonds between SdrG and the peptide backbone. If pulled, the load is distributed over all hydrogen bonds so that all bonds must be broken at once to break the interaction. Science , this issue p. 1527 ; see also p. 1464