Title
Global transition of human serum albumin to prefibrillar aggregates induced by temsirolimus: Insight into implications of anti-renal cancer drug
Author
Anas Shamsi, Azaj Ahmed, Bilqees Bano
Year
2017
Journal
Journal of Molecular Recognition
Abstract
In our study, we have characterized the prefibrillar aggregates of human serum albumin (HSA) induced by temsirolimus, anti-renal cancer drug. Molecular docking was retorted to confirm binding of HSA and temsirolimus. Temsirolimus caused the structural transition of native HSA to non-native species after prolonged incubation of 20 days. These non-native species were characterized as prefibrillar aggregates as evident by decreased intrinsic fluorescence and enhanced 8-anilino-1-naphthalene-sulphonic acid (ANS) fluorescence. Further, enhanced thioflavin T fluorescence and shift in congo red (CR) spectra of temsirolimus-incubated HSA as compared to native HSA are suggestive of global transition of HSA in presence of temsirolimus towards prefibrillar aggregates. Circular dichroism spectroscopy revealed α to β transition upon prolonged incubation with temsirolimus suggesting the formation of prefibrillar aggregates as aggregates are known to possess high β content. Scanning electron microscopy confirmed these non-native species to be prefibrillar aggregates evident by observed sheath-like structures. Comet assay was retorted to confirm genotoxic nature of these prefibrillar aggregates; DNA damage was observed for temsirolimus-incubated HSA confirming the genotoxic nature of prefibrillar aggregates. These prefibrillar aggregates are observed at heart of many pathological conditions, thus making our study clinically significant.
Instrument
J-810
Keywords
Circular dichroism, Secondary structure, Aggregation, Biochemistry