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Summary: pKa values of ionizable residues and isoelectric points of proteins provide valuable local and global insights about their structure and function. These properties can be estimated with reasonably good accuracy using Poisson-Boltzmann and Monte Carlo calculations at a considerable computational cost (from some minutes to several hours). pKPDB is a database of over 12 M theoretical pKa values calculated over 120k protein structures deposited in the Protein Data Bank. By providing precomputed pKa and pI values, users can retrieve results instantaneously for their protein(s) of interest while also saving countless hours and resources that would be spent on repeated calculations. Furthermore, there is an ever-growing imbalance between experimental pKa and pI values and the number of resolved structures. This database will complement the experimental and computational data already available and can also provide crucial information regarding buried residues that are under-represented in experimental measurements.
Availability And Implementation: Gzipped csv files containing p Ka and isoelectric point values can be downloaded from https://pypka.org/pKPDB. To query a single PDB code please use the PypKa free server at https://pypka.org. The pKPDB source code can be found at https://github.com/mms-fcul/pKPDB.
Supplementary Information: Supplementary data are available at Bioinformatics online.
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http://dx.doi.org/10.1093/bioinformatics/btab518 | DOI Listing |
Langmuir
September 2025
Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States.
The surfaces of 1D layered lepidocrocite-structured titanates (1DLs) are negatively charged due to an oxygen-to-titanium atomic ratio >2. This, and their layered structure, allow for facile ion exchange and high colloidal stability, demonstrated by ζ-potentials of ≈ -85 mV at their unadjusted pH of ≈10.4.
View Article and Find Full Text PDFEnviron Int
August 2025
Eawag: Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, 8600, Duebendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, Universitaetstrasse 16, 8092, Zurich, Switzerland. Electronic address:
Synthetic antioxidants (SAOs) are widely used additives in industrial and consumer products, yet their human exposure and fate throughout wastewater treatment remain poorly understood. This study investigates the occurrence of SAOs and their human metabolites in wastewater influent as well as their abatement in three wastewater treatment plants (WWTPs) employing both conventional and advanced treatment technologies. In vitro human liver S9 assays were performed to generate a SAO metabolite MS2 library containing over 2500 potential metabolites, which was matched against wastewater influent data.
View Article and Find Full Text PDFJ Phys Chem B
September 2025
Université de Lorraine, CNRS, GeoRessources, Nancy F-54000, France.
Quartz is among the most abundant minerals on Earth, but its surface chemistry under varying pH conditions remains not fully understood. In particular, the interplay between pH, amphoteric behavior, and water adsorption properties has been the subject of a long-standing debate. This study presents a comprehensive, multitechnique investigation into the pH-dependent interfacial chemistry of quartz.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2025
Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS Université de Strasbourg, Faculté de pharmacie 74 route du Rhin, 67401 Illkirch, France.
To fully exploit the potential of isothiazologuanosine (G), an isomorphic and isofunctional fluorescent analogue of guanosine, as a probe for DNA and RNA, we characterized its photophysics and in particular its excited-state reactions over a wide pH range (-0.6 to 12) and time scale (100 fs-100 ns) by combining transient absorption and time-correlated single photon counting measurements with quantum mechanical calculations. At acidic pH, the dominant ground-state species G-H1-H3, where the N atoms in positions 1 and 3 are protonated, rapidly converts to the more stable tautomer G-H1-H7 in its excited state.
View Article and Find Full Text PDFACS Synth Biol
September 2025
Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
Achieving efficient enzyme catalysis under extreme pH conditions remains a major challenge in biocatalysis and synthetic biology. To address this, we present an enzyme engineering strategy that integrates rational redesign of catalytic residues with directed evolution to enable robust enzyme function at alkaline pH. The core principle involves replacing the conserved general base with an ionizable residue of higher intrinsic p, shifting the proton transfer mechanism from carboxylate- to phenolate-mediated catalysis.
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