Calcium ion binding by isolated tobacco mosaic virus coat protein.
Calcium ion titrations were performed on solutions of tobacco mosaic virus coat protein using a calcium-specific ion-exchange electrode. Isolated coat protein was found incapable of binding calcium ions under equilibrium conditions at pH values above its iso-ionic point (pH 4.3 to 4.6). However, calcium ions were found to bind to coat protein under non-equilibrium conditions, which suggests that the isolated coat protein has the proper conformation to bind calcium ions at the iso-ionic point.
D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D004563:Electrochemistry; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D007474:Ion Exchange; D007700:Kinetics; D046911:Macromolecular Substances; D014027:Tobacco Mosaic Virus / Q000032:analysis*; D014764:Viral Proteins / Q000378:metabolism*; D014867:Water
D046911:Macromolecular Substances; D014764:Viral Proteins; D014867:Water; D002118:Calcium