Synthesis and conformational preferences of short analogues of antifreeze glycopeptides (AFGP)

• Małgorzata Urbańczyk,
• Michał Jewgiński,
• Joanna Krzciuk-Gula,
• Jerzy Góra,
• Rafał Latajka and
• Norbert Sewald

Beilstein J. Org. Chem. 2019, 15, 1581–1591, doi:10.3762/bjoc.15.162

• each hydroxy group in the threonine side chain is glycosylated with the disaccharide β-ᴅ-galactosyl-(1→3)-α-N-acetyl-ᴅ-galactosamine [4]. Even though the macroscopic properties of AFGPs, such as thermal hysteresis [5][6] and ice recrystallization inhibition [7][8][9] have been well described, the

• analogues, which occasionally occurs in smaller natural AFGP (and furthermore proline is a precursor of the PP II helix) significantly decreased the inhibitory effect on the ice recrystallization of the compounds [19]. Here we present the synthesis of a series of model peptides comprising structural motifs

Antifreeze glycopeptide diastereomers

• Lilly Nagel,
• Carsten Budke,
• Axel Dreyer,
• Thomas Koop and
• Norbert Sewald

Beilstein J. Org. Chem. 2012, 8, 1657–1667, doi:10.3762/bjoc.8.190

• replacement of L-threonine by its allo-L-diastereomer. Both glycopeptides were analyzed regarding their conformational properties, by circular dichroism (CD), and their ability to inhibit ice recrystallization in microphysical experiments. Keywords: bioorganic chemistry; circular dichroism; glycopeptides

• ; ice recrystallization; microwave chemistry; Introduction Several fish species living in polar and subpolar oceans have developed a strategy to survive in water at an average temperature of −1.8 °C. This non-colligative freezing-point depression is based on the prevention of ice growth in

• and the retro-inverso analogue 7 were tested in this study in an ice-recrystallization-inhibition assay [34][35][36][37]. In the absence of any active additives a polycrystalline ice sample undergoes Ostwald ripening at constant temperatures driven by the reduction of the total ice/solution interface