Journal Article10.1021/BI048655Q
A thermal unfolding study of plastocyanin from the thermophilic cyanobacterium Phormidium laminosum.
Maria J. Feio,José A. Navarro,Miguel Teixeira,David J Harrison,B. Göran Karlsson,Miguel A. De la Rosa +5 more
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TL;DR: The unfolding pH dependence and kinetic studies indicate a process with a tight control around the physiological pH in which plastocyanin plays its redox role and the protein's isoelectric point, suggesting a close compromise between function and stability.
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Abstract: The thermal unfolding of the plastocyanin from Phormidium laminosum, a thermophilic cyanobacterium, is herein described. The main objective of this work is to identify structural factors responsible for the higher stability observed in proteins from thermophilic organisms. With the aid of fluorescence spectroscopy, EPR, and NMR, the factors influencing the unfolding process of the protein were investigated, and procedures for its study have been standardized. The different spectroscopic techniques used provided consistent results showing that the thermal unfolding of plastocyanin is irreversible under all the conditions investigated and that this irreversibility does not appear to be related to the presence of oxygen. The oxidized plastocyanin species has proven to be more stable than the reduced one, with respect to both the required temperature for protein unfolding (up to a 9 °C difference between the two forms) and the kinetics of the process. The behavior of this plastocyanin contrasts with that of o...
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Citations
Different modes of interaction in cyanobacterial complexes of plastocyanin and cytochrome f.
Irene Díaz-Moreno,Antonio Díaz-Quintana,Miguel A. De la Rosa,Peter B. Crowley,Marcellus Ubbink +4 more
TL;DR: Differences in interactions between the soluble electron-transfer protein plastocyanin and it partner cytochrome f in photosynthesis are mainly attributable to the surface properties of the plastOCyanins.
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Thermostability of Proteins: Role of Metal Binding and pH on the Stability of the Dinuclear CuA Site of Thermus thermophilus
TL;DR: The dinuclear copper center (TtCuA) forming the electron entry site in the subunit II of the cytochrome c oxidase in Thermus thermophilus shows high stability toward thermal as well as denaturant-induced unfolding of the protein at ambient pH.
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Residue-level NMR view of the urea-driven equilibrium folding transition of SUMO-1 (1-97): native preferences do not increase monotonously.
TL;DR: It is observed by circular dichroism and fluorescence spectroscopy that urea-induced unfolding of this protein is a complex process with the possibility of occurrence of detectable intermediates along the way.
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Local structural preferences and dynamics restrictions in the urea-denatured state of SUMO-1: NMR characterization.
TL;DR: Investigation of the structural and dynamic characteristics of the urea-denatured state of activated SUMO-1, a 97-residue protein belonging to the growing family of ubiquitin-like proteins involved in post-translational modifications, finds many contiguous stretches of three or more residues exhibit structural propensities suggesting possibilities of short-range transient structure formation.
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Thermostability of glucose oxidase in silica gel obtained by sol-gel method and in solution studied by fluorimetric method.
TL;DR: Investigation of the enzyme in different environment by steady-state fluorescence of FAD and tryptophan, synchronous fluorescence and time-resolved fluorescence indicates that the state of the molecule (tertiary structure and molecular dynamics) is different in gel and in solution.
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