Two-dimensional correlation analysis of Raman optical activity data on the α-helix-to-β-sheet transition in poly(L-lysine)

Ashton, Lorna and Barron, Laurence D. and Czarnik-matusewicz, Boguslawa and Hecht, Lutz and Hyde, Jason and Blanch, Ewan W. (2006) Two-dimensional correlation analysis of Raman optical activity data on the α-helix-to-β-sheet transition in poly(L-lysine). Molecular Physics, 104 (9). pp. 1429-1445. ISSN 0026-8976

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Abstract

Raman optical activity (ROA) has evolved into an incisive probe of structure and conformational transitions in polypeptides and proteins revealing many signal patterns characteristic of specific secondary structural elements. In order to further facilitate analysis of ROA spectral intensity variations, two-dimensional correlation methods are applied to ROA and Raman spectra monitoring the α-helix-to-β-sheet transition in poly(L-lysine) as a function of temperature. Pretreatment of data using background subtraction, normalization and gentle smoothing is essential for the successful generation of 2D ROA correlations, 2D Raman correlations and 2D Raman/ROA heterocorrelations. The pseudoscalar nature of ROA spectra results in detailed 2D correlation analyses providing extensive interpretation of spectral intensity variations. Synchronous plots indicate band assignments consistent with established assignments in poly(L-lysine) together with possible new assignments. Corresponding asynchronous plots probe the temporal sequence of the conformational transition indicating distinct temporal phases while monitoring aggregation through a small amount of β-structure present at the start of the experiment ahead of α-helix unfolding. This study demonstrates the potential of 2D correlation analysis as a valuable technique for the extraction of detailed information about aggregation and conformational transitions in polypeptides and proteins from associated ROA and Raman spectra. Results indicate that aggregation of poly(L-lysine) monomers precedes intramolecular conversion of α-helix to β-sheet, which is then followed by fibril formation.

Item Type:
Journal Article
Journal or Publication Title:
Molecular Physics
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1300/1312
Subjects:
?? molecular biologyphysical and theoretical chemistrybiophysicscondensed matter physics ??
ID Code:
71954
Deposited By:
Deposited On:
28 Nov 2014 11:32
Refereed?:
Yes
Published?:
Published
Last Modified:
15 Jul 2024 14:55