Backbone and side chain 1H, 15N and 13C chemical shift assignments of the molten globule state of L94G mutant of horse cytochrome-c
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Proteins fold via a number of intermediates that help them to attain their unique native 3D structure. These intermediates can be trapped under extreme conditions of pH, temperature and chemical denaturants. Similar states can also be achieved by other processes like chemical modification, site directed mutagenesis (or point mutation) and cleavage of covalent bonds of natural proteins under physiological conditions usually taken as dilute buffer (near neutral pH) and 25 °C. Structural characterization of molten globules is hampered due to (i) their transient nature, (ii) very low population at equilibrium, and (iii) prone to aggregation at high concentration. Furthermore, the dynamic nature of these folding intermediates makes them unsuitable for X-ray diffraction. Hence, understanding their structures at the atomic level is often a challenge. However, characterization of these intermediates at the atomic level is possible by NMR, which could possibly unravel new details of the protein folding process. We have previously shown that the L94G mutant of horse cytochrome-c displays characteristics of the molten globule (MG) state at pH 6.0 and 25 °C. As a first step towards characterizing this MG state at the atomic level by NMR, we report its complete backbone, side chain and heme chemical shift assignments.
KeywordsNuclear magnetic resonance Protein folding Molten globule Chemical shift assignments Cytochrome-c
AN and FA and AI thank Indian Council of Medical Research (India) for the award of Senior Research Fellowship and for the financial support of the research. FA is grateful to Indian National Science Academy for the award of Senior Scientist position. MS is thankful to Department of Biotechnology (DBT), Govt. of India for financial and infrastructure support.
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Conflict of interest
The authors declare that they have no conflict of interest.
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