English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

A fluorescence probe is introduced for protein conformation and binding-site monitoring as the proton-transfer (PT) tautomer fluorescence by using 4-hydroxy-5-azaphenanthrene (HAP) as a prototype. A typical grossly-wavelength-shifted PT fluorescence for HAP is observed in the 600-nm spectral region for this UV-absorbing molecule (absorption onset, 400 nm), for which case PT occurs even in protic solvents. It is shown that PT fluorescence of HAP can serve as a protein-binding-site static-polarity calibrator, shifting from a lambda max of 612 nm in cyclohexane to 585 nm in ethanol at 298 K, contrary to the usual dispersion red shift. A small mechanical solvent-cage effect is noted in ethanol at 77 K, but solvent dielectric relaxation is not apparent from the fluorescence spectrum. Thus, HAP serves to distinguish static solvent-cage polarity from dynamical solvent dielectric relaxation and other solvent-cage effects (mechanical restriction of molecular conformation). HAP as a PT-fluorescence probe is applied to human serum albumin (HSA) and beaver apomyoglobin.

Excited-state intramolecular proton transfer as a fluorescence probe for protein binding-site static polarity.