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Milda Pucetaite
Forskare
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Deuterium-Enhanced Raman Spectroscopy for Histidine pKa Determination in a pH-Responsive Hydrogel
Författare
Summary, in English
We report here a method for the determination of the pKa of histidine in complex or heterogeneous systems amenable to neither solid-state nor solution NMR spectroscopy. Careful synthesis of a fluorenylmethyloxycarbonyl- and trityl-protected, C2-deuterated histidine produces a vibrational-probe-equipped amino acid that can readily be incorporated into any peptide accessible by standard solid-phase methods. The frequency of the unique, Raman-active stretching vibration of this C2-D probe is a clear reporter of the protonation state of histidine. We investigate here a pH-sensitive peptide that self-assembles to form a hydrogel at neutral pH. The pKa of the lone histidine residue in the peptide, which is likely responsible for this pH-dependent behavior, cannot be investigated by NMR spectroscopy because of the supramolecular, soft nature of the gel. However, after synthesizing a C2-deuterated-histidine-containing peptide, we were able to follow the protonation state of histidine throughout a pH titration using Raman difference spectroscopy, thereby precisely determining the pKa of interest.
Avdelning/ar
- Biokemi och Strukturbiologi
- BECC: Biodiversity and Ecosystem services in a Changing Climate
- Centrum för miljö- och klimatvetenskap (CEC)
Publiceringsår
2020
Språk
Engelska
Sidor
1701-1705
Publikation/Tidskrift/Serie
Biophysical Journal
Volym
119
Issue
9
Dokumenttyp
Artikel i tidskrift
Förlag
Cell Press
Ämne
- Biophysics
Aktiv
Published
ISBN/ISSN/Övrigt
- ISSN: 0006-3495