Hydrophobic and Hofmeister effects on the adhesion of spider silk proteins onto solid substrates: an AFM-based single-molecule study.
AFM-based single-molecule force spectroscopy has been used to study the effect of Hofmeister salts and protein hydrophobicity on the adhesion of recombinant spider silk proteins onto solid substrates. Therefore, a molecular probe consisting of a spider silk protein and an AFM tip has been developed, which (i) is a well-defined, small system that can be simulated by molecular dynamics simulations, (ii) allows access to the whole soluble concentration range for ions, and (iii) provides the distribution of desorption forces rather than just ensemble-averaged mean values. The measured desorption forces follow the Hofmeister series for anions (H2PO4-, Cl-, I-) with a stabilizing energy of more than 15 kBT for 5 M NaH2PO4. Moreover, this effect is influenced by the hydrophobicity of the spider silk protein, indicating that hydrophobic and Hofmeister effects are closely related.
IMETUM, Physics Department, Walter Schottky Institute, Technische Universität München, Garching, Germany.
Michael
M
Geisler
Tobias
T
Pirzer
Christian
C
Ackerschott
Simon
S
Lud
Jose
J
Garrido
Thomas
T
Scheibel
Thorsten
T
Hugel
D000818:Animals; D000838:Anions / Q000737:chemistry; D003198:Computer Simulation; D057927:Hydrophobic and Hydrophilic Interactions; D019476:Insect Proteins / Q000737:chemistry*; D008567:Membranes, Artificial; D018625:Microscopy, Atomic Force / Q000379:methods*; D008956:Models, Chemical; D009566:Nitrates / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry; D012492:Salts / Q000737:chemistry*; D047011:Silk / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D012974:Sodium Iodide / Q000737:chemistry; D013112:Spiders / Q000737:chemistry*; D013499:Surface Properties
D000838:Anions; D019476:Insect Proteins; D008567:Membranes, Artificial; D009566:Nitrates; D010710:Phosphates; D011994:Recombinant Proteins; D012492:Salts; D047011:Silk; D012965:Sodium Chloride; C031618:sodium nitrate; D012974:Sodium Iodide; C018279:sodium phosphate