Structural and functional factors in the hydrogen bonding of polar organic solvents to acid-soluble collagen. Effect on renaturation kinetics and thermal stability

Abstract

The effect of a number of polar organic solvents, including aliphatic alcohols, ethers, ketones, and nitriles, on the renaturation kinetics and stability of acid-soluble calfskin collagen has been investigated. The solvents reduced the rate

Molecular simulation of the effects of alcohols on peptide structure

“…It has been assumed that alcohols affect protein structure, in part, by displacing water molecules from hydrogen-bonding sites along the peptide backbone. 34,42 The influence of several factors have been examined, including the hydrogen-bond geometry and the chemical nature of the alcohol itself.…”

“…Nevertheless, these findings generally confirm the results from experimental analyses. Methylene chain length, 17,19,25 halogenation, 30 propensity for hydrogen bonding, 34,37 and changes in the solvent dielectric constant 57 have all been found to be important properties of alcohols that affect protein folding. Nonetheless, there has not been a unanimous agreement on a single mode of action by which alcohols modify the structure of peptides and proteins.…”

“…(1) Alcohols should form hydrogen bonds to the exposed peptide carbonyl groups much like water, but because they are weaker hydrogen-bond acceptors than water, the alcohols will interact minimally with the amide hydrogens. 34,45 (2) The hydrogen-bond geometry of the alcohol interaction should be similar to that of water molecules. The work of Baker and Hubbard, 46 Artymiuk and Blake, 47 and Sundaralingam and Sekharudu 48 has precisely defined the distances and angles involved in hydrogen-bond formation between peptide donors/acceptors and bound water.…”

“…For these studies, it was assumed that alcohols act as strong hydrogenbond donors at peptide carbonyl groups, essentially displacing bound water. 34,42 Furthermore, it was assumed that the hydrogen-bond geometries involving alcohols should resemble those of water molecules. The distances and angles used to define these sites were entirely consistent with those observed for water molecules forming hydrogen bonds with proteins.…”

“…34 -36). Although direct binding of alcohols to proteins has been demonstrated by a variety of methods, 28,34,37 it has also been persuasively argued that alcohols affect protein structure mainly through solvent effects. 21,36,38 A number of groups have proposed theoretical models to attempt to explain how alcohols (and other cosolvents) affect protein structure.…”