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BP: Fachverband Biologische Physik

BP 24: Posters - Protein Structure and Dynamics

BP 24.10: Poster

Dienstag, 21. März 2017, 14:00–16:00, P1A

Chiral effects in CH3->CF3 mutations in amino acids determine hydrophobicity — Joao Robalo¹, Susanne Huhmann², Beate Koksch², and •Ana Vila Verde¹ — ¹MPIKG, Theory and Bio-Systems Dept., Am Mühlenberg 1 OT Golm , 14476 Potsdam, Germany — ²Freie Universität Berlin, Institute of Chemistry and Biochemistry, Takustr. 3, 14195 Berlin

Protein fluorination is a promising avenue to modify protein properties. Predicting the impact of protein fluorination on protein stability based on simple heuristics - e.g., changes in amino acid apolar surface area or polarity - has proven impossible because of the interplay between the fluorinated site and its neighboring environment. Ultimately understanding and predicting how fluorination impacts proteins can best be done using molecular simulations and classical, atomistic models. Here we present such a model for fluorinated amino acids. We apply this force field to investigate how CH3->CF3 mutations alter the hydrophobicity of apolar amino acids. Our results show that these mutations increase the hydrophobicity of the amino acid directly, by increasing the apolar surface area, and indirectly, by decreasing the number of backbone-water hydrogen bonds. Strikingly, stereoisomeric effects strongly impact the conformational orientation and the flexibility of the amino acid side chain and ultimately determine the magnitude of changes in hydrophobicity. We demonstrate that the commonly accepted notion that CH3->CF3 mutations alter protein stability only via changes in apolar surface area is incorrect, and show that different fluorinated stereoisomers may be exploited for particular purposes.