title: Contribution of long-range interactions to the secondary structure of an unfolded globin.
abstract: This work explores the effect of long-range tertiary contacts on the distribution of residual secondary structure in the unfolded state of an alpha-helical protein. N-terminal fragments of increasing length, in conjunction with multidimensional nuclear magnetic resonance, were employed. A protein representative of the ubiquitous globin fold was chosen as the model system. We found that, while most of the detectable alpha-helical population in the unfolded ensemble does not depend on the presence of the C-terminal region (corresponding to the native G and H helices), specific N-to-C long-range contacts between the H and A-B-C regions enhance the helical secondary structure content of the N terminus (A-B-C regions). The simple approach introduced here, based on the evaluation of N-terminal polypeptide fragments of increasing length, is of general applicability to identify the influence of long-range interactions in unfolded proteins.
authors.affiliation: Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA.
authors.forename: Daria V
authors.initials: DV
authors.lastname: Fedyukina
authors.forename: Senapathy
authors.initials: S
authors.lastname: Rajagopalan
authors.forename: Ashok
authors.initials: A
authors.lastname: Sekhar
authors.forename: Eric C
authors.initials: EC
authors.lastname: Fulmer
authors.forename: Ye-Jin
authors.initials: YJ
authors.lastname: Eun
authors.forename: Silvia
authors.initials: S
authors.lastname: Cavagnero
mesh_terms: D000818:Animals; D001059:Apoproteins / Q000737:chemistry / Q000378:metabolism; D005914:Globins / Q000737:chemistry* / Q000378:metabolism*; D009211:Myoglobin / Q000737:chemistry / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D017433:Protein Structure, Secondary; D058767:Protein Unfolding
chemical_list: D001059:Apoproteins; D009211:Myoglobin; C010857:apomyoglobin; D005914:Globins
references.citation: Proc Natl Acad Sci U S A. 2008 Apr 29;105(17):6278-83
references.pmid: 18434548
references.citation: Eur Biophys J. 1994;23(4):297-305
references.pmid: 7805629
references.citation: Biochemistry. 2001 Mar 27;40(12):3561-71
references.pmid: 11297422
references.citation: J Mol Biol. 2002 Sep 27;322(4):655-62
references.pmid: 12270702
references.citation: J Mol Biol. 1991 Nov 20;222(2):311-33
references.pmid: 1960729
references.citation: Chem Rev. 2004 Aug;104(8):3607-22
references.pmid: 15303830
references.citation: Proc Natl Acad Sci U S A. 2004 Aug 24;101(34):12497-502
references.pmid: 15314216
references.citation: J Mol Biol. 2006 Jan 27;355(4):809-20
references.pmid: 16309705
references.citation: Biochemistry. 2005 Aug 30;44(34):11369-80
references.pmid: 16114874
references.citation: J Biomol NMR. 2002 Nov;24(3):245-62
references.pmid: 12522312
references.citation: Curr Opin Struct Biol. 2005 Feb;15(1):35-41
references.pmid: 15718131
references.citation: Crit Rev Biochem Mol Biol. 2005 Jul-Aug;40(4):181-9
references.pmid: 16126485
references.citation: Proc Natl Acad Sci U S A. 2004 Aug 24;101(34):12491-6
references.pmid: 15314214