title: Electronic interactions of i, i + 1 dithioamides: increased fluorescence quenching and evidence for n-to-π* interactions.
abstract: Thioamide residues can be effective, minimally-perturbing fluorescence quenching probes for studying protein folding and proteolysis. In order to increase the level of quenching, we have here explored the use of adjacent dithioamides. We have found that they are more effective fluorescence quenchers, as expected, but we have also observed unexpected changes in the thioamide absorption spectra that may arise from n-to-π* interactions of the thiocarbonyls. We have made use of the increased quenching to improve the fluorescence turn-on of thioamide protease sensors.
authors.affiliation: Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA. ejpetersson@sas.upenn.edu.
authors.forename: Yun
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA. ejpetersson@sas.upenn.edu.
authors.forename: John J
authors.initials: JJ
authors.lastname: Ferrie
authors.affiliation: Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA. ejpetersson@sas.upenn.edu.
authors.forename: Xing
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA. ejpetersson@sas.upenn.edu.
authors.forename: Yitao
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA. ejpetersson@sas.upenn.edu and Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania, Perelman School of Medicine, 3700 Hamilton Walk, Philadelphia, PA 19104, USA.
authors.forename: D Miklos
authors.initials: DM
authors.lastname: Szantai-Kis
authors.affiliation: Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA. ejpetersson@sas.upenn.edu.
authors.forename: David M
authors.initials: DM
authors.lastname: Chenoweth
authors.affiliation: Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA. ejpetersson@sas.upenn.edu.
authors.forename: E James
authors.initials: EJ
authors.lastname: Petersson