Nano-scale morphology of melanosomes revealed by small-angle X-ray scattering

  • Melanosomes are highly specialized organelles that produce and store the pigment melanin, thereby fulfilling essential functions within their host organism. Besides having obvious cosmetic consequences – determining the color of skin, hair and the iris – they contribute to photochemical protection from ultraviolet radiation, as well as to vision (by defining how much light enters the eye). Though melanosomes can be beneficial for health, abnormalities in their structure can lead to adverse effects. Knowledge of their ultrastructure will be crucial to gaining insight into the mechanisms that ultimately lead to melanosome-related diseases. However, due to their small size and electron-dense content, physiologically intact melanosomes are recalcitrant to study by common imaging techniques such as light and transmission electron microscopy. In contrast, X-ray-based methodologies offer both high spatial resolution and powerful penetrating capabilities, and thus are well suited to study the ultrastructure of electron-dense organelles in their natural, hydrated form. Here, we report on the application of small-angle X-ray scattering – a method effective in determining the three-dimensional structures of biomolecules – to whole, hydrated murine melanosomes. The use of complementary information from the scattering signal of a large ensemble of suspended organelles and from single, vitrified specimens revealed a melanosomal sub-structure whose surface and bulk properties differ in two commonly used inbred strains of laboratory mice. Whereas melanosomes in C57BL/6J mice have a well-defined surface and are densely packed with 40-nm units, their counterparts in DBA/2J mice feature a rough surface, are more granular and consist of 60-nm building blocks. The fact that these strains have different coat colors and distinct susceptibilities to pigment-related eye disease suggest that these differences in size and packing are of biological significance.

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Author:Thomas GorniakGND, Tamás HarasztiGND, Vasyl M. GaramusORCiDGND, Andreas Robert von GundlachGND, Tobias SenkbeilGND, Marius PriebeGND, Adam Hedberg-BuenzGND, Demelza KoehnGND, Tim SaldittGND, Michael GrunzeGND, Michael G. AndersonGND, Axel RosenhahnORCiDGND
URN:urn:nbn:de:hbz:294-73276
DOI:https://doi.org/10.1371/journal.pone.0090884
Parent Title (English):PLoS ONE
Publisher:Public Library of Science
Place of publication:San Francisco
Document Type:Article
Language:English
Date of Publication (online):2020/07/14
Date of first Publication:2014/03/12
Publishing Institution:Ruhr-Universität Bochum, Universitätsbibliothek
Volume:9
Issue:3, Artikel e90884
First Page:e90884-1
Last Page:e90884-8
Note:
Korrektur zum Artikel:

1 Jul 2014: The PLOS ONE Staff (2014) Correction: Nano-Scale Morphology of Melanosomes Revealed by Small-Angle X-Ray Scattering. PLOS ONE 9(7): e101746.
https://doi.org/10.1371/journal.pone.0101746
Institutes/Facilities:Arbeitsgruppe Analytische Chemie - Biointerfaces
open_access (DINI-Set):open_access
Licence (German):License LogoCreative Commons - CC0 1.0 - Universell - Public Domain Dedication