Fluorine–hydrogen interactions observed in a helix structure having an orn-free gramicidin S sequence incorporating 4-trans-fluoroproline
Year: 2025
Type: article
Abstract: The decapeptide Boc-(D-Phe-tFPro-Val-Leu-Leu)2—OMe (1) (Boc is tert-butoxycarbonyl, tFPro is 4-trans-fluoro-L-proline D-Phe is D-phenylalanine, Val is valine and Leu is leucine) crystallized in a methanol-solvated form (C68H104F2N10O13·CH4O). Peptide 1 has a sequence similar to gramicidin S (GS) incorporating tFPro. GS is a cyclic peptide, with the D-Phe-Pro unit known as a strong β-turn inducer in previous studies. Thus, it was initially assumed that 1 would bend at the D-Phe6-tFPro7 position, potentially forming a sheet-like structure. However, the structure of 1 was a helix, a surprising finding in GS-related structural studies. A factor enabling this helical formation could be the fluorine–H interactions between tFPro and the aromatic rings of D-Phe residues.
Authors: Asano Akiko, Mizuki Sakata, Kato Takuma, Mitsunobu Doi
Institution: Osaka Medical and Pharmaceutical University
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $500
OpenAlex ID: W4408912142