Insight into the secondary structure of chloramphenicol acetyltransferase type I - computer analysis and FT-IR spectroscopic characterization of the protein structure

The secondary structure of chloramphenicol O-acetyltransferase type I (CAT I) and an N-terminal deleted mutant has been studied by Fourier transform infrared spectroscopy. The analysis of the amide I band of different samples (KBr, hydrated films and buffer solution) by Fourier self-deconvolution followed by a curve fitting was performed. The spectroscopic data have been utilized to determine the alpha -helix and beta -structure % contents, which depend strongly on the protein sample preparation. Furthermore, the secondary structure of the enzyme-inhibitor Crystal Violet complex was analyzed. The observed difference in the secondary structural contents suggests that some conformational changes of the enzyme are induced by the inhibitor after binding. (C) 2001 Elsevier Science B.V. All rights reserved.