Fluoroalcohol-induced stabilization of the α-helical intermediates of lentil lectin: implication for non-hierarchical lectin folding

How methyl cyanide induces aggregation in all-alpha proteins: A case study in four albumins

“…With increase in MeCN concentration, in the presence of 20% (v/v) MeCN in BSA, 5% in HSA, 10% in PSA and 30% in RSA (spectra 2) significant increase in the negative minima was observed, due to increase in ␣-helical structures [35]. Further increase in MeCN concentration, i.e., 75%, 70%, 55% and 90% MeCN (v/v) (spectra 4) on BSA, HSA, PSA and RSA respectively has produced spectra with positive ellipticity near 208 nm and negative maxima near 230 nm, which is similar to the spectra of concanavalin A. Concanavalin A is an all ␤-sheet protein, exhibits this unusual type of far UV CD band [36,37]. The far UV CD studies have shown that serum albumin; a predominantly ␣-helical protein turns into non-native ␤-sheet conformations as MeCN concentration increases.…”

Effect of polyamines on the structure, thermal stability and 2,2,2-trifluoroethanol-induced aggregation of α-chymotrypsin

“…It is well known that various alcohols, especially those substituted with fluorine such as TFE, can stabilize and induce ␣-helical structures in peptides and proteins [19][20][21][22][23][24][25][26]29]. To monitor the TFE-induced changes in ␣-chymotrypsin secondary structure, the mean-residue ellipticity of the protein at 208 and 217 nm, which are normally regarded as indicators of ␣-helix and ␤-strand abundance, was measured at various TFE concentrations.…”

“…Various alcohols, especially those substituted with fluorine such as 2,2,2-trifluoroethanol (TFE) and 3,3,3,3 ,3 ,3 -hexafluoro-2-propanol (HFIP) have been found very effective in causing protein denaturation and inducing ␣-helical structure in peptides [20][21][22][23]. This effect can presumably be attributed to low dielectric constants of alcohols [24,25].…”

“…Alcohol-induced conformational transitions of proteins have been found to be similar to those induced by the lipid environment of biological membranes [28], making such studies useful regarding protein conformation in membranes. Furthermore, characterizing the alcohol-induced intermediate states of the proteins may shed light on the mechanism of their folding [22,23,29].…”

Peptide T exhibits a well‐defined structure in fluorinated solvent at low temperature

“…Fluorinated alcohols, such as HFIP, provide an additional means to induce peptide structure36, 37. Aqueous mixtures comprised of TFE and HFIP are some of the most effective solvents to stabilize protein structure, with HFIP having a much stronger effect than TFE38–41. The effects of alcohol on protein structure have been shown to arise from the low polarity of the solvent, which leads to the strengthening of local electrostatic interactions, such as hydrogen bonds.…”