title: Thermal stability of lysozyme as a function of ion concentration: a reappraisal of the relationship between the Hofmeister series and protein stability.
abstract: Anion and cation effects on the structural stability of lysozyme were investigated using differential scanning calorimetry. At low concentrations (<5 mM) anions and cations alter the stability of lysozyme but they do not follow the Hofmeister (or inverse Hofmeister) series. At higher concentrations protein stabilization follows the well-established Hofmeister series. Our hypothesis is that there are three mechanisms at work. At low concentrations the anions interact with charged side chains where the presence of the ion can alter the structural stability of the protein. At higher concentrations the low charge density anions perchlorate and iodide interact weakly with the protein. Their presence however reduces the Gibbs free energy required to hydrate the core of the protein that is exposed during unfolding therefore destabilizing the structure. At higher concentrations the high charge density anions phosphate and sulfate compete for water with the protein as it unfolds increasing the Gibbs free energy required to hydrate the newly exposed core of the protein therefore stabilizing the structure.
authors.affiliation: Department of Chemical and Biological Engineering, ChELSI Institute, University of Sheffield, Sheffield, S1 3JD, England, United Kingdom.
authors.forename: Jordan W
authors.initials: JW
authors.lastname: Bye
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Falconer
mesh_terms: D000818:Animals; D000838:Anions / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D002412:Cations / Q000737:chemistry*; D004795:Enzyme Stability; D005260:Female; D008956:Models, Chemical; D009113:Muramidase / Q000737:chemistry*; D017510:Protein Folding; D012492:Salts / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D000838:Anions; D002412:Cations; D012492:Salts; D009113:Muramidase
keywords: DSC; Hofmeister; calorimeter; chaotrope; formulation; kosmotrope
references.citation: Protein Sci. 2002 Jul;11(7):1771-8
references.pmid: 12070329
references.citation: Q Rev Biophys. 1985 Nov;18(4):323-422
references.pmid: 3916340
references.citation: J Am Chem Soc. 2004 Feb 25;126(7):1958-61
references.pmid: 14971928
references.citation: Proc Natl Acad Sci U S A. 1995 Sep 12;92(19):8926-9
references.pmid: 7568045
references.citation: J Agric Food Chem. 2013 Jan 16;61(2):290-5
references.pmid: 23252762
references.citation: Biochemistry. 2007 Jan 23;46(3):917-23
references.pmid: 17223714
references.citation: Proteins. 2000 Jul 1;40(1):29-38
references.pmid: 10813828
references.citation: Proc Natl Acad Sci U S A. 2007 Dec 26;104(52):20749-52
references.pmid: 18093918
references.citation: Proc Natl Acad Sci U S A. 2009 Sep 8;106(36):15249-53
references.pmid: 19706429
references.citation: Biochim Biophys Acta. 1996 Oct 17;1297(2):171-81
references.pmid: 8917619
references.citation: Science. 2003 Jul 18;301(5631):347-9
references.pmid: 12869755
references.citation: Chemphyschem. 2013 Feb 4;14(2):386-93
references.pmid: 23281099
references.citation: J Am Chem Soc. 2008 Aug 6;130(31):10345-53
references.pmid: 18624406
references.citation: Biophys Chem. 2012 Apr;163-164:56-63
references.pmid: 22414801
references.citation: Curr Opin Chem Biol. 2006 Dec;10(6):658-63
references.pmid: 17035073
references.citation: Biophys Chem. 2008 Jun;135(1-3):25-31
references.pmid: 18395318
references.citation: Protein Sci. 1998 Mar;7(3):689-97
references.pmid: 9541401
references.citation: Biochim Biophys Acta. 2006 Oct;1764(10):1546-52
references.pmid: 17015045
references.citation: Opt Express. 2010 Dec 20;18(26):27431-44
references.pmid: 21197019
references.citation: J Phys Chem B. 2013 Jan 17;117(2):490-4
references.pmid: 23240622
references.citation: J Mol Biol. 1990 May 20;213(2):385-91
references.pmid: 2160545
references.citation: J Biol Chem. 2003 Jun 20;278(25):22187-92
references.pmid: 12676939
references.citation: Arch Biochem Biophys. 2008 Nov 1;479(1):69-73
references.pmid: 18782555
references.citation: Biophys J. 1997 Jan;72(1):65-76
references.pmid: 8994593
references.citation: Biophys J. 2008 Aug;95(3):1285-94
references.pmid: 18441020
references.citation: Annu Rev Phys Chem. 2010;61:63-83
references.pmid: 20055667
references.citation: J Mol Biol. 1990 May 20;213(2):375-84
references.pmid: 2342113
references.citation: Biochemistry. 1990 Apr 10;29(14):3480-8
references.pmid: 2162192
references.citation: Proc Natl Acad Sci U S A. 1995 Jun 6;92(12):5553-7
references.pmid: 7539920
references.citation: J Biol Chem. 1965 Oct;240(10):3909-23
references.pmid: 5842063
references.citation: Protein Sci. 1992 Sep;1(9):1133-43
references.pmid: 1304392