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Characterization of heat induced spherulites of lysozyme reveals new insight on amyloid initiation.

DIR@IMTECH: CSIR-Institute of Microbial Technology

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Title Characterization of heat induced spherulites of lysozyme reveals new insight on amyloid initiation.
 
Creator Sharma, Pankaj
Verma, Neha
Singh, Pradip Kumar
Korpole, Suresh
Ashish, .
 
Subject QR Microbiology
 
Description Here, we report results obtained during our experiments to visualize how heat transforms globular protein, lysozyme into building block of β-amyloids. Light scattering experiments showed formation of lower order associated species around 50-70 °C followed by rapid cooperativity to β-amyloid fibrils. Interestingly, crystallization drops set at higher temperatures either led to aggregates or spherulites. The latter possess an amorphous β-fibril rich core with thin crystalline needles projecting outwards. Diffraction of the crystalline outgrowths revealed novel dimers and trimers of lysozyme where individual chains were similar to monomer with marginal gain in β-sheet content. Importantly, analysis of Amide I stretching frequencies showed that protein loses its secondary structure at temperatures higher than where we obtained crystals followed by rapid gain in β-sheet content. Interestingly, attempts to use the needles as seeds for more crystals led to "broom-like" fibril formations at the ends. Further, aggregation inhibitors like arginine and benzyl alcohol completely obliterated spherulites formation during crystallization. Refinement of crystals of lysozyme in presence of these molecules showed these small molecules bind to the interfaces of heat associated dimers and trimers. Overall our work concludes that heat induced weakly associated structures of lysozyme are the first step towards its amyloid formation.
 
Publisher NPG
 
Date 2016
 
Type Article
PeerReviewed
 
Format application/pdf
 
Identifier http://crdd.osdd.net/open/1905/1/82.pdf
Sharma, Pankaj and Verma, Neha and Singh, Pradip Kumar and Korpole, Suresh and Ashish, . (2016) Characterization of heat induced spherulites of lysozyme reveals new insight on amyloid initiation. Scientific reports, 6. p. 22475. ISSN 2045-2322
 
Relation http://www.nature.com/articles/srep22475
http://crdd.osdd.net/open/1905/