Author:
Schmitz Mirko,Schultze Anne,Vanags Raimonds,Voigt Karsten,Di Ventura Barbara,Öztürk Mehmet Ali
Abstract
AbstractpH regulates protein function and interactions by altering the charge of individual residues causing the loss or gain of intra-molecular non-covalent bonds, which may additionally lead to structural rearrangements. While tools to analyze residue-specific charge distribution of protein sequences and structures at a given pH exist, currently no tool is available to investigate non-covalent bond changes at two different pH values. In an effort to make protein pH sensitivity analysis more accessible to researchers without computational structural biology background, we developed patcHwork, a web server that combines the identification of amino acids undergoing a charge shift with the determination of affected non-covalent bonds at two user-defined pH values. At the sequence-only level, patcHwork applies the Henderson-Hasselbalch equation to determine pH-sensitive residues. When the 3D protein structure is available, patcHwork can be employed to gain a deeper mechanistic understanding of the effect of pH on a protein of interest. This is achieved using the PDB2PQR and PROPKA tools and non-covalent bond determination algorithms. A user-friendly interface allows visualizing pH-sensitive residues as well as affected salt bridges, hydrogen bonds and aromatic (pi-pi and cation-pi) interactions. Importantly, patcHwork can be used to identify patches, a new concept we propose of pH-sensitive residues in close proximity on the protein structure, which may have a major impact on function. We demonstrate the attractiveness of patcHwork studying experimentally investigated pH-sensitive proteins. (Access:https://patchwork.biologie.uni-freiburg.de/)Graphical abstract
Publisher
Cold Spring Harbor Laboratory