Heat induces end to end repetitive association in P. furiosus l-asparaginase which enables its thermophilic property

Abstract It remains undeciphered how thermophilic enzymes display enhanced stability at elevated temperatures. Taking l-asparaginase from P. furiosus (PfA) as an example, we combined scattering shapes deduced from small-angle X-ray scattering (SAXS) data at increased temperatures with symmetry mates...

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Main Authors: Pankaj Sharma, Rachana Tomar, Shivpratap Singh Yadav, Maulik D. Badmalia, Samir Kumar Nath, Ashish, Bishwajit Kundu
Format: article
Language:EN
Published: Nature Portfolio 2020
Subjects:
R
Q
Online Access:https://doaj.org/article/cb4ab17049d744219a90d1b286d8a31c
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Summary:Abstract It remains undeciphered how thermophilic enzymes display enhanced stability at elevated temperatures. Taking l-asparaginase from P. furiosus (PfA) as an example, we combined scattering shapes deduced from small-angle X-ray scattering (SAXS) data at increased temperatures with symmetry mates from crystallographic structures to find that heating caused end-to-end association. The small contact point of self-binding appeared to be enabled by a terminal short β-strand in N-terminal domain, Leu179-Val-Val-Asn182 (LVVN). Interestingly, deletion of this strand led to a defunct enzyme, whereas suplementation of the peptide LVVN to the defunct enzyme restored structural frameworkwith mesophile-type functionality. Crystal structure of the peptide-bound defunct enzyme showed that one peptide ispresent in the same coordinates as in original enzyme, explaining gain-of lost function. A second peptide was seen bound to the protein at a different location suggesting its possible role in substrate-free molecular-association. Overall, we show that the heating induced self-assembly of native shapes of PfA led to an apparent super-stable assembly.