Secondary-structure contents of the peptides

As expected, adsorbed peptides do not exhibit clear structures at room temperature. In Fig. 14,11, the respective a-helix and /3-stand contents of the adsorbed conformations, ria)b and ( )b, respectively, are shown. Although noticeable differences for the mentioned peptide groups are found, there is no significant population of a-helical or /3-sheet structures, at least at room temperature. Nonetheless, there is a tendency that residues of SI and S3 are rather in a and residues of S3 and SI in /3 state. The small secondary-structure contents are quite similar to what was observed for the peptides in solution (without substrate see Fig. 14,5), It is obvious that the presence of the Si(lOO) substrate does not lead to a stabilization of secondary stmctures here. Such stabilization can occur, however, and has been reported, for example, for a synthetic peptide binding at silica nanoparticles [358]. 

Gyration tensor components of the peptides (a) perpendicuiar and (b) paraiiei to the substrate. For comparison, resuits for the peptides in soivent only (i.e., without substrate) are aiso shown. 

6 Sequence-specific peptide adsorption at silicon (100) surface 

---