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Superior photoprotective motifs and mechanisms in eumelanins uncovered.

Corani, Alice LU ; Huijser, Annemarie LU ; Gustavsson, Thomas; Markovitsi, Dimitra; Malmqvist, Per-Åke LU ; Pezzella, Alessandro; d'Ischia, Marco and Sundström, Villy LU (2014) In Journal of the American Chemical Society 136(33). p.11626-11635
Abstract
Human pigmentation is a complex phenomenon commonly believed to serve a photoprotective function through the generation and strategic localization of black insoluble eumelanin biopolymers in sun exposed areas of the body. Despite compelling biomedical relevance to skin cancer and melanoma, eumelanin photoprotection is still an enigma: What makes this pigment so efficient in dissipating the excess energy brought by harmful UV-light as heat? Why has Nature selected 5,6-dihydroxyindole-2-carboxylic acid (DHICA) as the major building block of the pigment instead of the decarboxylated derivative (DHI)? By using pico- and femtosecond fluorescence spectroscopy we demonstrate herein that the excited state deactivation in DHICA oligomers is 3... (More)
Human pigmentation is a complex phenomenon commonly believed to serve a photoprotective function through the generation and strategic localization of black insoluble eumelanin biopolymers in sun exposed areas of the body. Despite compelling biomedical relevance to skin cancer and melanoma, eumelanin photoprotection is still an enigma: What makes this pigment so efficient in dissipating the excess energy brought by harmful UV-light as heat? Why has Nature selected 5,6-dihydroxyindole-2-carboxylic acid (DHICA) as the major building block of the pigment instead of the decarboxylated derivative (DHI)? By using pico- and femtosecond fluorescence spectroscopy we demonstrate herein that the excited state deactivation in DHICA oligomers is 3 orders of magnitude faster compared to DHI oligomers. This drastic effect is attributed to their specific structural patterns enabling multiple pathways of intra- and interunit proton transfer. The discovery that DHICA-based scaffolds specifically confer uniquely robust photoprotective properties to natural eumelanins settles a fundamental gap in the biology of human pigmentation and opens the doorway to attractive advances and applications. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of the American Chemical Society
volume
136
issue
33
pages
11626 - 11635
publisher
The American Chemical Society
external identifiers
  • pmid:25078723
  • wos:000340737900017
  • scopus:84906347104
ISSN
1520-5126
DOI
10.1021/ja501499q
language
English
LU publication?
yes
id
41235808-ca8d-4996-80cc-b1135b5de91d (old id 4615909)
date added to LUP
2014-09-12 16:49:32
date last changed
2017-07-23 03:27:47
@article{41235808-ca8d-4996-80cc-b1135b5de91d,
  abstract     = {Human pigmentation is a complex phenomenon commonly believed to serve a photoprotective function through the generation and strategic localization of black insoluble eumelanin biopolymers in sun exposed areas of the body. Despite compelling biomedical relevance to skin cancer and melanoma, eumelanin photoprotection is still an enigma: What makes this pigment so efficient in dissipating the excess energy brought by harmful UV-light as heat? Why has Nature selected 5,6-dihydroxyindole-2-carboxylic acid (DHICA) as the major building block of the pigment instead of the decarboxylated derivative (DHI)? By using pico- and femtosecond fluorescence spectroscopy we demonstrate herein that the excited state deactivation in DHICA oligomers is 3 orders of magnitude faster compared to DHI oligomers. This drastic effect is attributed to their specific structural patterns enabling multiple pathways of intra- and interunit proton transfer. The discovery that DHICA-based scaffolds specifically confer uniquely robust photoprotective properties to natural eumelanins settles a fundamental gap in the biology of human pigmentation and opens the doorway to attractive advances and applications.},
  author       = {Corani, Alice and Huijser, Annemarie and Gustavsson, Thomas and Markovitsi, Dimitra and Malmqvist, Per-Åke and Pezzella, Alessandro and d'Ischia, Marco and Sundström, Villy},
  issn         = {1520-5126},
  language     = {eng},
  number       = {33},
  pages        = {11626--11635},
  publisher    = {The American Chemical Society},
  series       = {Journal of the American Chemical Society},
  title        = {Superior photoprotective motifs and mechanisms in eumelanins uncovered.},
  url          = {http://dx.doi.org/10.1021/ja501499q},
  volume       = {136},
  year         = {2014},
}