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Publication Abstract from PubMed

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 beta-strand in N-terminal domain, Leu(179)-Val-Val-Asn(182) (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.

Heat induces end to end repetitive association in P. furiosus L-asparaginase which enables its thermophilic property.,Sharma P, Tomar R, Yadav SS, Badmalia MD, Nath SK, Ashish, Kundu B Sci Rep. 2020 Dec 10;10(1):21702. doi: 10.1038/s41598-020-78877-z. PMID:33303914^[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.