eprintid: 17221
rev_number: 22
userid: 1419
dir: disk0/00/01/72/21
datestamp: 2013-02-08 21:06:42
lastmod: 2021-06-12 23:55:35
status_changed: 2013-02-08 21:06:42
type: article
metadata_visibility: show
item_issues_count: 0
eprint_status: archive
creators_name: Lu, M
creators_name: Ahmed, Z
creators_name: Mikhonin, AV
creators_name: Asher, SA
creators_email: 
creators_email: 
creators_email: 
creators_email: asher@pitt.edu
creators_id: 
creators_id: 
creators_id: 
creators_id: ASHER
title: UV resonance raman measurements of poly-L-lysine's conformational energy landscapes: Dependence on perchlorate concentration and temperature
ispublished: pub
divisions: sch_as_chemistry
full_text_status: public
abstract: UV resonance Raman spectroscopy has been used to determine the conformational energy landscape of polyL-lysine (PLL) in the presence of NaClO4 as a function of temperature. At 1 °C, in the presence of 0.83 M NaClO4, PLL shows an ∼86% α-helix-like content, which contains ́-helix and π-bulge/helix conformations. The high a-helix-like content of PLL occurs because of charge screening due to strong ion-pair formation between ClO4- and the lysine side chain -NH3+. As the temperature increases from 1 to 60 °C, the ́-helix and π-bulge/helix conformations melt into extended conformations (PPII and 2.51-helix). We calculate the Ψ Ramachandran angle distribution of the PLL peptide bonds from the UV Raman spectra which allows us to calculate the PLL (un)folding energy landscapes along the Ψ reaction coordinate. We observe a basin in the Ψ angle conformational space associated with α-helix and π-bulge/helix conformations and another basin for the extended PPII and 2.5 1-helical conformations. © 2007 American Chemical Society.
date: 2007-07-05
date_type: published
publication: Journal of Physical Chemistry B
volume: 111
number: 26
pagerange: 7675 - 7680
refereed: TRUE
issn: 1520-6106
id_number: 10.1021/jp0703758
pmid: 17567063
mesh_headings: Circular Dichroism
mesh_headings: Perchloric Acid--chemistry
mesh_headings: Polylysine--chemistry
mesh_headings: Protein Conformation
mesh_headings: Protein Folding
mesh_headings: Sodium Compounds--chemistry
mesh_headings: Spectrophotometry, Ultraviolet
mesh_headings: Spectrum Analysis, Raman
mesh_headings: Temperature
mesh_headings: Thermodynamics
chemical_names: Sodium Compounds
chemical_names: Polylysine
chemical_names: Perchloric Acid
chemical_names: sodium perchlorate
citation:   Lu, M and Ahmed, Z and Mikhonin, AV and Asher, SA  (2007) UV resonance raman measurements of poly-L-lysine's conformational energy landscapes: Dependence on perchlorate concentration and temperature.  Journal of Physical Chemistry B, 111 (26).  7675 - 7680.  ISSN 1520-6106     
document_url: http://d-scholarship-dev.library.pitt.edu/17221/1/licence.txt