Study on hemorrhagin III purified from the venom of Agkistrodon acutus by three-dimensional fluorescence spectrometry

The conformation changes of hemorrhagin III in different media were studied by three-dimensional fluorescence spectrometry (TDFS). It was found that t he emission band of the protein remained centered at 344 nm for different e xcitation wavelengths in 0.1% sodium dodecyl sulfate (SDS) or in 0.05% cety ltrimethyl ammonium bromide (CTAB), as did that of apo-AaH III, while a red -shift occurred in 5.0 M guanidine hydrochloride (Gu-HCl). Changes in the e nvironments of tryptophan (Trp) residues responsible for those in emission could be readily seen in the TDF contours. It was confirmed from the TDF sp ectra that Trp residues were mainly located in hydrophilic environments at the surface of the AaH III molecule. The experimental data showed that envi ronments of Trp residues and protein conformational changes are effectively and directly revealed by TDFS. (C) 1999 Elsevier Science B.V. All rights r eserved.