title: Folding of a heterogeneous β-hairpin peptide from temperature-jump 2D IR spectroscopy.
abstract: We provide a time- and structure-resolved characterization of the folding of the heterogeneous β-hairpin peptide Tryptophan Zipper 2 (Trpzip2) using 2D IR spectroscopy. The amide I' vibrations of three Trpzip2 isotopologues are used as a local probe of the midstrand contacts, β-turn, and overall β-sheet content. Our experiments distinguish between a folded state with a type I' β-turn and a misfolded state with a bulged turn, providing evidence for distinct conformations of the peptide backbone. Transient 2D IR spectroscopy at 45 °C following a laser temperature jump tracks the nanosecond and microsecond kinetics of unfolding and the exchange between conformers. Hydrogen bonds to the peptide backbone are loosened rapidly compared with the 5-ns temperature jump. Subsequently, all relaxation kinetics are characterized by an observed 1.2 ± 0.2-μs exponential. Our time-dependent 2D IR spectra are explained in terms of folding of either native or nonnative contacts from a common compact disordered state. Conversion from the disordered state to the folded state is consistent with a zip-out folding mechanism.
authors: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors: Kevin C
authors: KC
authors: Jones
authors: Chunte Sam
authors: CS
authors: Peng
authors: Andrei
authors: A
authors: Tokmakoff
mesh_terms: D006860:Hydrogen Bonding; D007700:Kinetics; D010455:Peptides / Q000737:chemistry*; D017510:Protein Folding; D013055:Spectrophotometry, Infrared / Q000379:methods*; D013696:Temperature
chemical_list: D010455:Peptides
references: J Phys Chem B. 2011 May 12;115(18):5415-24
references: 21388153
references: Phys Chem Chem Phys. 2010 Aug 28;12(32):9347-57
references: 20596553
references: J Am Chem Soc. 2004 Jun 30;126(25):7758-9
references: 15212506
references: Nat Struct Biol. 1997 Jan;4(1):10-9
references: 8989315
references: J Phys Chem A. 2009 Dec 24;113(51):14060-6
references: 19938867
references: J Chem Phys. 2004 Jan 15;120(3):1477-90
references: 15268273
references: J Am Chem Soc. 2011 Dec 7;133(48):19338-41
references: 22066714
references: J Chem Phys. 2007 Apr 21;126(15):155101
references: 17461665
references: Proc Natl Acad Sci U S A. 2004 Mar 23;101(12):4077-82
references: 15020773
references: J Phys Chem B. 2009 Apr 23;113(16):5661-74
references: 19326892
references: Nature. 1997 Nov 13;390(6656):196-9
references: 9367160
references: Proc Natl Acad Sci U S A. 2009 Nov 10;106(45):19011-6
references: 19887634
references: Proc Natl Acad Sci U S A. 1999 Aug 3;96(16):9068-73
references: 10430896
references: Proc Natl Acad Sci U S A. 2004 Sep 28;101(39):14102-7
references: 15377792
references: J Phys Chem B. 2010 Sep 2;114(34):10913-24
references: 20690697
references: J Am Chem Soc. 2008 Oct 22;130(42):13938-44
references: 18811160
references: Proc Natl Acad Sci U S A. 2011 Jul 5;108(27):11087-92
references: 21690352
references: J Am Chem Soc. 2008 Mar 12;130(10):2984-92
references: 18278908
references: Angew Chem Int Ed Engl. 2007;46(42):7984-7
references: 17853520
references: J Phys Chem B. 2005 Sep 15;109(36):17025-7
references: 16853169
references: Protein Sci. 1999 Jun;8(6):1166-80
references: 10386867
references: Proc Natl Acad Sci U S A. 2007 Sep 4;104(36):14237-42
references: 17551015
references: Nature. 2006 Nov 23;444(7118):469-72
references: 17122853
references: Rev Sci Instrum. 2007 Jun;78(6):063101
references: 17614599
references: J Phys Chem B. 2009 Jun 18;113(24):8288-95
references: 19469524
references: Proteins. 2006 Mar 15;62(3):672-85
references: 16362933
references: J Chem Phys. 2006 Apr 14;124(14):141102
references: 16626172
references: Biochemistry. 2005 Aug 2;44(30):10406-15
references: 16042418
references: J Mol Biol. 2009 Jul 17;390(3):538-46
references: 19450609
references: Proc Natl Acad Sci U S A. 2001 May 8;98(10):5578-83
references: 11331745
references: J Phys Chem B. 2007 Aug 23;111(33):9993-8
references: 17676791
references: Proc Natl Acad Sci U S A. 2004 Nov 9;101(45):15915-20
references: 15520391
references: Proc Natl Acad Sci U S A. 2008 Jul 15;105(28):9588-93
references: 18621686
references: J Phys Chem B. 2009 Jan 22;113(3):803-8
references: 19113829
references: J Chem Phys. 2006 Jan 28;124(4):044502
references: 16460180
references: J Phys Chem B. 2010 Sep 9;114(35):11628-37
references: 20707354
references: J Phys Chem B. 2010 Mar 18;114(10):3735-40
references: 20166694
references: J Mol Biol. 2004 Feb 6;336(1):241-51
references: 14741219