Berlin 2008 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 9: POSTERS Single Molecules, Biopolymers, Membranes

CPP 9.18: Poster

Montag, 25. Februar 2008, 16:45–19:00, Poster A

AFM Studies of Langmuir-Blodgett Films of Acidic Peptides — •Manuela Pluntke¹, Haofei Gong², Yi Yang³, Norbert Sewald³, Dirk Volkmer², and Othmar Marti¹ — ¹Institute of Experimental Physics, Ulm University, D-89069 Ulm — ²Institute of Inorganic Chemistry II, Ulm University, D-89069 Ulm — ³Faculty of Chemistry (AC 1), University of Bielefeld, PO Box 100 131, 33501 Bielefeld

Acidic proteins are found to play an important role in biomineralization. Extracted from different calcified tissues, they were shown to control polymorph selection, texture and morphology of CaCO₃ crystals. We recently fabricated Langmuir-Blodgett Monolayers of different artificial acidic peptides with β-hairpin conformation (H-Asp-(Phe-Asp)₃-D-Pro-Gly-Asp-(Phe-Asp)₃OH, H-Glu-(Phe-Glu)₃-D-Pro-Gly-Glu-(Phe-Glu)₃OH). Circular Dichroism Spectra show that these two peptides take a random coil and β-sheet structure in HFIP solution, respectively. At the air/water interface, significant differences of the peptide monolayer properties were found as revealed by surface pressure-area isotherms and BAM, although they have similar primary structure. Moreover, crystallization of CaCO₃ beneath these monolayers revealed different crystal morphologies. For a more detailed analysis of the peptide arrangement at interfaces we transfered the monolayers on mica and investigated them by means of high resolution AFM. Based on preliminary studies we assume that only the peptide H-Glu-(Phe-Glu)₃-D-Pro-Gly-Glu-(Phe-Glu)₃OH forms a highly ordered lattice of hairpin structures.