Molten globules stability

Bam NB, Cleland JL, Randolph TW. Molten globule intermediate of recombinant human growth hormone stabilization with surfactants. Biotechnol Prog 1996 12(6) 801—809. 

The calcium ion in a-LA plays a structural role in stabilizing the protein. The thermal stability of the calcium-bound form of a-LA increases more than 40 °C compared to that of the apo-form. At low pH (e.g. pH 2), a-LA releases the calcium ion and becomes partially unfolded (molten globule state). This partially unfolded protein loses its tertiary structure but retains its secondary structure. Other metals, such as manganese or magnesium, are able to compete with calcium at the same site with a similar stabilizing effect. However, the binding of zinc, which is proposed to bind at different locations, decreases a-LA stability. ... 

Morozova, L. A., Haynie, D. T., Arico-Muendel, C., Van Dael, H. Dobson, C. M. (1995). Structural Basis of the Stability of a Lysozyme Molten Globule. Nature Structural Biology 2,871-875. 

Shutova T, Irrgang K-D, Klimov W et al. Is the manganese stabilizing 33 kDa protein of photosystem II attaining a natively unfolded or a molten globule structure in solution FEBS Lett 2000 467 137-140. 

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