Abstract
Single molecule force spectroscopy is a valuable tool for studying unfolding and nanomechanical properties of proteins. The common practice is to stretch proteins from a surface that was dosed to give a reasonable hit rate and to analyze the curves that exhibit the expected characteristics of a single polymer. Whether the surface-bound proteins are indeed single and isolated remains unclear, and the undesirable protein/surface interactions that obscure informative features of the force curves are implicitly assumed to be absent. In this study, mixed self-assembled monolayers (SAMs) consisting of N-hydroxysuccinimide (NHS) and oligoethylene glycol (OEG) terminated thiols on an ultraflat gold surface were used to covalently immobilize proteins via lysine residues. By the optimization of attachment sites via lysine-NHS linkages amidst a protein-resistant layer of the OEG SAM, it was possible to isolate single proteins for study in a controlled fashion. The single protein distribution on the surface is clearly demonstrated by atomic force microscopy (AFM) imaging. The OEG also significantly reduces nonspecific tip-surface interactions between the cantilever and surface. Stretching covalently attached single proteins produces high-quality and reproducible force-extension curves. This experimental strategy is an attractive platform with which to study protein structure, interactions, and nanomechanical properties of single proteins.
Original language | English |
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Pages (from-to) | 6969-6976 |
Number of pages | 8 |
Journal | Langmuir |
Volume | 22 |
Issue number | 16 |
DOIs | |
Publication status | Published - Aug 1 2006 |
Externally published | Yes |
ASJC Scopus subject areas
- General Materials Science
- Condensed Matter Physics
- Surfaces and Interfaces
- Spectroscopy
- Electrochemistry