title: The role of solution conditions in the bacteriophage PP7 capsid charge regulation.
abstract: We investigate and quantify the effects of pH and salt concentration on the charge regulation of the bacteriophage PP7 capsid. These effects are found to be extremely important and substantial, introducing qualitative changes in the charge state of the capsid such as a transition from net-positive to net-negative charge depending on the solution pH. The overall charge of the virus capsid arises as a consequence of a complicated balance with the chemical dissociation equilibrium of the amino acids and the electrostatic interaction between them, and the translational entropy of the mobile solution ions, i.e., counterion release. We show that to properly describe and predict the charging equilibrium of viral capsids in general, one needs to include molecular details as exemplified by the acid-base equilibrium of the detailed distribution of amino acids in the proteinaceous capsid shell.
authors.affiliation: Department of Biomedical Engineering, Department of Chemistry, and Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois.
authors.forename: Rikkert J
authors.initials: RJ
authors.lastname: Nap
authors.affiliation: Max Planck Institute for Biology of Ageing, Cologne, Germany.
authors.forename: Anže Lošdorfer
authors.initials: AL
authors.lastname: Božič
authors.affiliation: Department of Biomedical Engineering, Department of Chemistry, and Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois. Electronic address: igalsz@northwestern.edu.
authors.forename: Igal
authors.initials: I
authors.lastname: Szleifer
authors.affiliation: Department of Theoretical Physics, Jožef Stefan Institute, Ljubljana, Slovenia; Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia; Department of Physics, University of Massachusetts, Amherst, Massachusetts. Electronic address: podgornik@physics.umass.edu.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Podgornik
mesh_terms: D002213:Capsid / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D017909:Levivirus / Q000737:chemistry*; D008954:Models, Biological; D054712:Salinity; D012996:Solutions; D055672:Static Electricity
chemical_list: D012996:Solutions