ArticleBiophysical journal2012
Comprehensive determination of protein tyrosine pKa values for photoactive yellow protein using indirect 13C NMR spectroscopy.
Article in Biophysical journal, 2012. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 14 papers.
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14 citing papers in PubMed, 23 citations in OpenAlex.
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- Phosphate- and pH-dependent self-assembly of recombinant spider silk proteins.Protein science : a publication of the Protein Society · 2026Article
- An MD View of Ligand Binding.Molecules (Basel, Switzerland) · 2025Article
- A Chemical Mechanistic Path Leads the Way to Cellular Argpyrimidine.Journal of the American Chemical Society · 2025Article
- Formation of a Purple Product upon the Reaction of ABTS Radicals with Proteins.International journal of molecular sciences · 2023Article
- Tryptophan Can Promote Oxygen Reduction to Water in a Biosynthetic Model of Heme Copper Oxidases.Biochemistry · 2023Article
- Experimental pKChembiochem : a European journal of chemical biology · 2019Article
- Conformation and dynamics of soluble repetitive domain elucidates the initial β-sheet formation of spider silk.Nature communications · 2018Article
- Active-Site pKa Determination for Photoactive Yellow Protein Rationalizes Slow Ground-State Recovery.Biophysical journal · 2017Article
- Joint neutron crystallographic and NMR solution studies of Tyr residue ionization and hydrogen bonding: Implications for enzyme-mediated proton transfer.Proceedings of the National Academy of Sciences of the United States of America · 2015Article
- pH-dependent random coil (1)H, (13)C, and (15)N chemical shifts of the ionizable amino acids: a guide for protein pK a measurements.Journal of biomolecular NMR · 2014Article
- Ground-state proton transfer kinetics in green fluorescent protein.Biochemistry · 2014Article
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Authors and funding
7 authors at 2 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Upon blue-light irradiation, the bacterium Halorhodospira halophila is able to modulate the activity of its flagellar motor and thereby evade potentially harmful UV radiation. The 14 kDa soluble cytosolic photoactive yellow protein (PYP) is believed to be the primary mediator of this photophobic response, and yields a UV/Vis absorption spectrum that closely matches the bacterium's motility spectrum. In the electronic ground state, the para-coumaric acid (pCA) chromophore of PYP is negatively charged and forms two short hydrogen bonds to the side chains of Glu-46 and Tyr-42. The resulting acid triad is central to the marked pH dependence of the optical-absorption relaxation kinetics of PYP. Here, we describe an NMR approach to sequence-specifically follow all tyrosine side-chain protonation states in PYP from pH 3.41 to 11.24. The indirect observation of the nonprotonated (13)C(γ) resonances in sensitive and well-resolved two-dimensional (13)C-(1)H spectra proved to be pivotal in this effort, as observation of other ring-system resonances was hampered by spectral congestion and line-broadening due to ring flips. We observe three classes of tyrosine residues in PYP that exhibit very different pK(a) values depending on whether the phenolic side chain is solvent-exposed, buried, or hydrogen-bonded. In particular, our data show that Tyr-42 remains fully protonated in the pH range of 3.41-11.24, and that pH-induced changes observed in the photocycle kinetics of PYP cannot be caused by changes in the charge state of Tyr-42. It is therefore very unlikely that the pCA chromophore undergoes changes in its electrostatic interactions in the electronic ground state.
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