A Bimane‐Based Peptide Staple for Combined Helical Induction and Fluorescent Imaging. (24th August 2020)

• Record Type: Journal Article
• Authors: Horsfall, Aimee J.; Dunning, Kylie R.; Keeling, Kelly L.; Scanlon, Denis B.; Wegener, Kate L.; Abell, Andrew D.
• Is Part Of: Chembiochem. Volume 21:Number 23(2020)
• Page Start: 3423
• Page End: 3432
• Publication Date: 2020-08-24
• Subjects: bimane -- fluorescence -- helical structures -- peptide staple -- peptidomimetics; Biochemistry -- Periodicals; Molecular biology -- Periodicals; Pharmaceutical chemistry -- Periodicals; 572
• DOI: 10.1002/cbic.202000485
• Languages: English
• ISSNs: 1439-4227

Abstract

Abstract: The thiol‐selective fluorescent imaging agent, dibromobimane, has been repurposed to crosslink cysteine‐ and homocysteine‐containing peptides, with the resulting bimane linker acting as both a structural constraint and a fluorescent tag. Macrocyclisation was conducted on nine short peptides containing two cysteines and/or homocysteines, both on‐resin and in buffered aqueous solution, to give macrocycles ranging in size from 16 ( i, i +2) to 31 ( i, i +7) atoms. The structures were defined by CD, NMR structure calculations by using Xplor‐NIH, NMR secondary shift and J HαNH analyses to reveal helical structure in the i, i +4 (1, 2 ), and i, i +3 (5 ) constrained peptides. Cellular‐uptake studies were conducted with three of the macrocycles. Subsequent confocal imaging revealed punctate fluorescence within the cytosol indicative of peptides trapped in endocytic vesicles. These studies demonstrate that dibromobimane is an effective tool for defining secondary structure within short peptides, whilst simultaneously introducing a fluorescent tag suitable for common cell‐based experiments. Abstract : Two in one : A repurposed fluorescent thiol labelling agent, dibromobimane, is used to form a peptide constraint to introduce helical structure into short peptides. The cyclisation can be conducted on‐resin following SPPS or in solution. The resultant inherently fluorescent peptides are compatible with cell‐uptake imaging experiments and mitigate the need to introduce a secondary tag.