title: Metal ion dependence of a heat-modifiable protein from the outer membrane of Escherichia coli upon sodium dodecyl sulfate-gel electrophoresis.
abstract: One heat-modifiable protein of Escherichia coli outer membrane does not completely change to the high-temperature form in the presence of magnesium ion in sodium dodecyl sulfate solution. When the metal ion complexing reagents ethylenediaminetetraacetic acid, phosphate ion, hydroxyl ion, or the competitive cations Zn2+ or Ca2+ are added to the sodium dodecyl sulfate-solubilized sample of outer membrane, and then the sample is heated to 100 degrees C and recooled to room temperature, the protein is almost completely converted to the high-temperature form. In control samples, or if sodium chloride, magnesium chloride, or manganous chloride are added to these samples and treated the same way, a large amount of the low-temperature form of the protein is preserved. beta-Mercaptoethanol additions gave the same results as the metal ion complexing reagents and may owe its activity in these solutions to metal-binding activity and not to its role as a reducing reagent. We concluded that magnesium ion may be involved with stabilization of the low-temperature form of the protein either by directly binding the magnesium or by mediating interaction with other components of the membrane.
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis*; D002473:Cell Wall / Q000032:analysis / Q000187:drug effects; D004492:Edetic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000032:analysis* / Q000187:drug effects; D006358:Hot Temperature; D008274:Magnesium / Q000494:pharmacology*; D008623:Mercaptoethanol / Q000494:pharmacology; D008970:Molecular Weight; D010710:Phosphates / Q000494:pharmacology; D011487:Protein Conformation; D012967:Sodium Dodecyl Sulfate; D012995:Solubility
chemical_list: D001426:Bacterial Proteins; D010710:Phosphates; D012967:Sodium Dodecyl Sulfate; D008623:Mercaptoethanol; D004492:Edetic Acid; D008274:Magnesium