Conformational studies of the trypsin-aluminum(III) complex in solution byRaman and Fourier transform infrared attenuated total reflectance spectroscopy

This paper presents the results of Raman and Fourier transform IR studies i nvestigating the interaction between AI(III) and trypsin, carried out in or der to understand better how Al(III) can modify the biological properties o f this proteolytic enzyme. The results indicate that Al(III) influences the secondary structure of trypsin. The trypsin-Al(III) complex in aqueous sol ution presents a molecular conformation similar to that of the trypsin-Al(I II) crystal determined by x-ray diffraction analysis, but differs from the structure of both solid trypsin and trypsin in aqueous solution when; analy zed in the absence of AI(III). In particular, the interaction of the protei n with aluminum in solution induces a decrease in the percentage of alpha-h elix and an increase in the percentage of beta-sheet and random coil, Solid trypsin and trypsin in solution also displayed differences in secondary st ructure in the absence of Al(III). Copyright (C) 1999 John Wiley & Sons, Lt d.