The physical state of water in living cells and model systems. XII. The influence of the conformation of a protein on the solubility of Na+ (sulfate), sucrose, glycine and urea in the water in which the protein is also dissolved.
In this report, we describe the result of an extensive investigation of the effects of the conformations of proteins on the solvency of the bulk-phase water in which the proteins are dissolved. The concentrations of the proteins used were usually between 20 to 40%; the temperature was 25 degrees +/- 1 degree C. To probe the solvency of the water, the apparent equilibrium distribution coefficients (or p-values) of 4 solutes were studied: Na+ (sulfate), glycine, sucrose, and urea. From 8 to 14 isolated proteins in three types of conformations were investigated: native; denatured by agents that unravel the secondary structure (e.g., alpha-helix, beta-pleated sheet) of the protein (i.e., 9 M urea, 3 M guanidine HCl); denatured by agents that only disrupt the tertiary structure but leave the secondary structure intact or even strengthened (i.e., 0.1 M sodium dodecylsulfate or SDS, 2 M n-propanol). The results are as follows: (1) as a rule, native proteins have no or weak effect on the solvency of the water for all 4 probes; (2) exposure to 0.1 M SDS and to 2 M n-propanol, as a rule, does not significantly decrease the p-value of all 4 probes; (3) exposure to 9 M urea and to 3 M guanidine HCl consistently lowers the p-values of sucrose, glycine and Na+ (sulfate) and equally consistently produces no effect on the p-value of urea. Sucrose, glycine, and Na+ are found in low concentrations in cell water while urea is not. These experiments were designed and carried out primarily to test two subsidiary theories of the AI hypotheses: the polarized multilayer (PM) theory of cell water; and the theory of size-dependent solute exclusion.(ABSTRACT TRUNCATED AT 400 WORDS)
Ling
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Damadian Foundation for Basic and Cancer Research, FONAR Corporation, Melville, New York 11747.
Ochsenfeld
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D000433:1-Propanol / Q000494:pharmacology; D000818:Animals; D001834:Body Water / Q000502:physiology*; D005998:Glycine / Q000494:pharmacology; D006146:Guanidines / Q000494:pharmacology; D007700:Kinetics; D011487:Protein Conformation; D011489:Protein Denaturation; D011506:Proteins / Q000502:physiology; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D012995:Solubility; D013395:Sucrose / Q000494:pharmacology; D013431:Sulfates / Q000494:pharmacology; D014508:Urea / Q000494:pharmacology
D006146:Guanidines; D011506:Proteins; D013431:Sulfates; C012036:sodium sulfate; D012967:Sodium Dodecyl Sulfate; D013395:Sucrose; D014508:Urea; D000433:1-Propanol; D005998:Glycine