creators_name: Shukla, Anshuman
creators_name: Mukherjee, Sourav
creators_name: Sharma, Swati
creators_name: Agrawal, Vishal
creators_name: Radha Kishan, K V
creators_name: Guptasarma, Purnananda
type: article
datestamp: 2012-01-08 05:46:15
lastmod: 2012-04-02 09:19:34
metadata_visibility: show
title: A novel UV laser-induced visible blue radiation from protein crystals and aggregates: scattering artifacts or fluorescence transitions of peptide electrons delocalized through hydrogen bonding?
ispublished: pub
subjects: QD
full_text_status: restricted
keywords: Peptide fluorescence; Delocalized electrons; Blue radiation; UV illumination
note: Copyright of this article belongs to Elsevier Science.
abstract: Proteins lacking prosthetic groups and/or cofactors are known to undergo electronic excitation transitions only upon exposure to UV-C (< 280 nm) and UV-B (280-320 nm), but not UV-A (320-400 nm) photons. Here, we report the discovery of a novel excitation that peaks at approximately 340 nm and yields visible violet-blue radiation with apparent band maxima at approximately 425, 445, 470, and 500 nm. All proteins and large polypeptides examined in solid form, and in solutions, display this quenchable and photobleachable radiation which can be established not owing to aromatic sidechains. As a note of caution, we wish to state that we have not been able to completely eliminate the possibility that the radiation may be an artifact owing to second order effects such as, e.g., Raman scattering of Raman-scattered photons; however, we assert that all our experiments indicate that the radiation actually owes to some form of fluorescence. We propose that peptide electrons that have been delocalized through intramolecular or intermolecular hydrogen bond formation display these long-wavelength electronic transitions. If confirmed by future studies, this preliminary discovery may turn out to have important implications for biomolecular spectroscopy, protein crystallography, and materials science.
date: 2004-08-15
date_type: published
publication: Archives of biochemistry and biophysics
volume: 428
number: 2
publisher: Elsevier Science
pagerange: 144-53
refereed: TRUE
issn: 0003-9861
official_url: http://www.sciencedirect.com/science/article/pii/S0003986104002693
related_url_url: http://www.sciencedirect.com/science/article/pii/S0003986104002693
related_url_type: pub
citation:   Shukla, Anshuman and Mukherjee, Sourav and Sharma, Swati and Agrawal, Vishal and Radha Kishan, K V and Guptasarma, Purnananda  (2004) A novel UV laser-induced visible blue radiation from protein crystals and aggregates: scattering artifacts or fluorescence transitions of peptide electrons delocalized through hydrogen bonding?  Archives of biochemistry and biophysics, 428 (2).  pp. 144-53.  ISSN 0003-9861     
document_url: http://crdd.osdd.net/open/206/1/guptasarma2004.pdf