title: Amide temperature coefficients in the protein G B1 domain.
abstract: Temperature coefficients have been measured for backbone amide (1)H and (15)N nuclei in the B1 domain of protein G (GB1), using temperatures in the range 283-313 K, and pH values from 2.0 to 9.0. Many nuclei display pH-dependent coefficients, which were fitted to one or two pK(a) values. (1)H coefficients showed the expected behaviour, in that hydrogen-bonded amides have less negative values, but for those amides involved in strong hydrogen bonds in regular secondary structure there is a negative correlation between strength of hydrogen bond and size of temperature coefficient. The best correlation to temperature coefficient is with secondary shift, indicative of a very approximately uniform thermal expansion. The largest pH-dependent changes in coefficient are for amides in loops adjacent to sidechain hydrogen bonds rather than the amides involved directly in hydrogen bonds, indicating that the biggest determinant of the temperature coefficient is temperature-dependent loss of structure, not hydrogen bonding. Amide (15)N coefficients have no clear relationship with structure.
authors.affiliation: Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK.
authors.forename: Jennifer H
authors.initials: JH
authors.lastname: Tomlinson
authors.forename: Mike P
authors.initials: MP
authors.lastname: Williamson
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013210:Staphylococcus / Q000166:cytology; D013696:Temperature
chemical_list: D001426:Bacterial Proteins
references.citation: J Biomol NMR. 2009 Mar;43(3):131-43
references.pmid: 19137264
references.citation: J Mol Biol. 2002 Apr 12;317(5):739-52
references.pmid: 11955021
references.citation: Magn Reson Chem. 2007 Feb;45(2):175-8
references.pmid: 17154329
references.citation: J Biomol NMR. 2001 Nov;21(3):249-61
references.pmid: 11775741
references.citation: Proteins. 2010 May 15;78(7):1652-61
references.pmid: 20112422
references.citation: Structure. 2005 Nov;13(11):1677-84
references.pmid: 16271891
references.citation: J Biomol NMR. 1995 Sep;6(2):135-40
references.pmid: 8589602
references.citation: J Am Chem Soc. 2009 Apr 8;131(13):4674-84
references.pmid: 19281232
references.citation: Biochemistry. 1992 Apr 14;31(14):3597-603
references.pmid: 1567818
references.citation: Biochemistry. 2001 Aug 28;40(34):10115-39
references.pmid: 11513590
references.citation: Biochemistry. 2004 Oct 19;43(41):13012-7
references.pmid: 15476394
references.citation: Biochem Biophys Res Commun. 1969 Jul 23;36(2):194-202
references.pmid: 5799638
references.citation: J Biomol NMR. 1997 Jun;9(4):359-69
references.pmid: 9255942
references.citation: J Am Chem Soc. 2001 Apr 4;123(13):2970-8
references.pmid: 11457007
references.citation: Proteins. 2010 Nov 1;78(14):3000-16
references.pmid: 20715051
references.citation: Biochemistry. 1994 Apr 19;33(15):4721-9
references.pmid: 8161530
references.citation: J Magn Reson. 2002 Aug;157(2):178-80
references.pmid: 12323135