Differential scanning calorimetry is an efficient tool to study and thermodynamically describe biological macromolecules, proteins and lipids, and complex biological systems. It has been applied in investigations of thylakoid membranes and membrane fragments since the 80s, but only recently an attempt has been made to describe the sequence of the thermally induced events. Herein, we further elaborate this approach by reviewing the results obtained on intact thylakoids from wild type plants and the chlorophyll b-less mutant chlorina f2, isolated lamellar aggregates of the major light-harvesting complex of photosystem II, grana and stroma membranes. The comparison of the revealed thermal transitions allowed the assignment of the calorimetric features associated with the melting of the major photosynthetic complexes in thylakoid membranes. This basic knowledge will be of great help to follow and compare the thermal stability of photosynthetic complexes under stress conditions and in a variety of mutants. The thermal behavior of another type of an energy-producing membrane, the purple membrane of Haloarchaea, is also reviewed. Although it represents a much more simple membrane system, it exhibits a complex melting profile that resembles the one found for the major light-harvesting complex of photosystem II.
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