title: Quenching ofp-Cyanophenylalanine Fluorescence by Various Anions.
abstract: To expand the spectroscopic utility of the non-natural amino acidp-cyanophenylalanine (PheCN), we examine the quenching efficiencies of a series of commonly encountered anions toward its fluorescence. We find that iodide exhibits an unusually large Stern-Volmer quenching constant, making it a convenient choice in PheCNfluorescence quenching studies. Indeed, using the villin headpiece subdomain as a testbed we demonstrate that iodide quenching of PheCNfluorescence offers a convenient means to reveal protein conformational heterogeneity. Furthermore, we show that the amino group of PheCNstrongly quenches its fluorescence, suggesting that PheCNcould be used as a local pH sensor.
authors: Department of Chemistry, University of Pennsylvania, 231 South 34 Street, Philadelphia, PA 19104, USA.
authors: Ileana M
authors: IM
authors: Pazos
authors: Rachel M
authors: RM
authors: Roesch
authors: Feng
authors: F
authors: Gai
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