Dodine as a Protein Denaturant: The Best of Two Worlds?

Abstract

Traditional denaturants such as urea and guanidinium ion unfold proteins in a cooperative “all-or-none” fashion. However, their high working concentration in combination with their strong absorption in the far ultraviolet region make it impossible to measure high quality circular dichroism or infrared spectra, which are commonly used to detect changes in protein secondary structure. On the other hand, detergents such as dodecyl sulfate destabilize native protein conformation at low millimolar concentrations and are UV transparent, but they do denature proteins more gradually than guanidinium or urea. In this work we studied the denaturation properties of the fungicide dodecylguanidinium acetate (dodine), which combines both denaturants into one. We show that dodine unfolds some small proteins at millimolar concentrations, facilitates temperature denaturation, and is transparent enough at its working concentration, unlike guanidinium, to measure full range circular dichroism spectra. Our results also suggest that dodine allows fine-tuning of the protein’s unfolded state, unlike traditional “all-or-none” denaturants.

Dodine as a transparent protein denaturant for circular dichroism and infrared studies

“…This could explain why urea is a weaker denaturant for a mixed alpha/beta fold such as PGK. On the basis of our experience with mini‐proteins, we expect that dodine will act at concentrations roughly 1000 times lower than guanidine, and 2000 times lower than urea …”

“…Because the solubility of the commercially available dodine acetate is low in pure water, dodine was pre‐dissolved in small amounts of ethanol (15 m M unless stated otherwise) and then diluted down to experimental concentrations (sub‐mM concentrations). Dodine concentrations were below the critical micelle concentration (CMC = 8.7 m M ) for all experiments …”

“…We showed that dodine denatures two miniproteins cooperatively at sub-mM concentrations, at least 10003 lower than the active concentration range of urea or guanidine. 11 It was less effective for the b-sheet model protein than for the helical bundle model protein.…”

DODİN FUNGUSİTİNİN Vicia faba L. BİTKİSİNDE TOTAL PROTEİN MİKTARI VE PEROKSİDAZ AKTİVİTESİ ÜZERİNE ETKİSİ

“…They also suggest that dodine allows fine tuning of the protein's unfolded state, unlike traditional "all-or-none" denaturants. But researchers have noted that the effectiveness of dodine is protein-dependent such as the five-helix bundle λ6−85, and the triple stranded β-sheet Fip35 WW domain [41].…”

Proteins in a brave new surfactant world

“…I end this review with a study that describes a rather striking chemical fusion between detergency and denaturancy, namely the compound dodine or dodecyl guanidinium acetate 64 . This compound, already described more than 30 years ago 65 , combines the denaturing potency of the guanido group with the self-assembling properties of the alkyl chain, and was studied in the hope of obtaining a denaturant that would be sufficiently potent to be employed at low mM concentrations so as to avoid the annoyingly strong absorption in the far-UV region displayed by urea and GdmCl at molar concentrations.…”