Single molecule force spectroscopy reveals that the oxidation state of cobalt ions plays an important role in enhancing the mechanical stability of proteins

Nanoscale ◽  
2019 ◽  
Vol 11 (42) ◽  
pp. 19791-19796 ◽  
Author(s):  
Jiahao Xia ◽  
Jiacheng Zuo ◽  
Hongbin Li

The binding of Co(iii) to the bi-histidine metal chelation site significantly enhances protein's mechanical stability.

Science ◽  
2018 ◽  
Vol 359 (6383) ◽  
pp. 1527-1533 ◽  
Author(s):  
Lukas F. Milles ◽  
Klaus Schulten ◽  
Hermann E. Gaub ◽  
Rafael C. Bernardi

High resilience to mechanical stress is key when pathogens adhere to their target and initiate infection. Using atomic force microscopy–based single-molecule force spectroscopy, we explored the mechanical stability of the prototypical staphylococcal adhesin SdrG, which targets a short peptide from human fibrinogen β. Steered molecular dynamics simulations revealed, and single-molecule force spectroscopy experiments confirmed, the mechanism by which this complex withstands forces of over 2 nanonewtons, a regime previously associated with the strength of a covalent bond. The target peptide, confined in a screwlike manner in the binding pocket of SdrG, distributes forces mainly toward the peptide backbone through an intricate hydrogen bond network. Thus, these adhesins can attach to their target with exceptionally resilient mechanostability, virtually independent of peptide side chains.


2015 ◽  
Vol 11 ◽  
pp. 817-827 ◽  
Author(s):  
Manuel Gensler ◽  
Christian Eidamshaus ◽  
Maurice Taszarek ◽  
Hans-Ulrich Reissig ◽  
Jürgen P Rabe

Multivalent biomolecular interactions allow for a balanced interplay of mechanical stability and malleability, and nature makes widely use of it. For instance, systems of similar thermal stability may have very different rupture forces. Thus it is of paramount interest to study and understand the mechanical properties of multivalent systems through well-characterized model systems. We analyzed the rupture behavior of three different bivalent pyridine coordination complexes with Cu2+ in aqueous environment by single-molecule force spectroscopy. Those complexes share the same supramolecular interaction leading to similar thermal off-rates in the range of 0.09 and 0.36 s−1, compared to 1.7 s−1 for the monovalent complex. On the other hand, the backbones exhibit different flexibility, and we determined a broad range of rupture lengths between 0.3 and 1.1 nm, with higher most-probable rupture forces for the stiffer backbones. Interestingly, the medium-flexible connection has the highest rupture forces, whereas the ligands with highest and lowest rigidity seem to be prone to consecutive bond rupture. The presented approach allows separating bond and backbone effects in multivalent model systems.


2018 ◽  
Vol 6 (32) ◽  
pp. 5303-5312 ◽  
Author(s):  
Lichao Liu ◽  
Han Wang ◽  
Yueying Han ◽  
Shanshan Lv ◽  
Jianfeng Chen

Mechanical stability of Ca2+-responsive β-roll peptides (RTX) is largely responsible for the Ca2+-dependent mechanical properties of the RTX-based hydrogels.


RSC Advances ◽  
2020 ◽  
Vol 10 (66) ◽  
pp. 40543-40551
Author(s):  
Mohd. Muddassir

A HA–RuII complex was conjugated to a hyaluronan polymer through amide bonds. In AFM experiments using the “multi-fishhook” approach, the cantilever tip made contact with the polymeric molecule, resulting in stretching, indicated by sawtooth-like force-extension curves.


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