A Fourier Transform Infrared Spectroscopic Investigation of Macrovipera lebetina lebetina and M. l. obtusa Crude Venoms

Objective: Snake venoms are rich sources of bioactive molecules and have been investigated using various bioanalytical methods. Fourier transform infrared (FTIR) spectroscopy is a sensitive method that can be used to analyze biological samples. The aim of this study is to apply the FTIR spectroscopy method for the characterization of snake venom. Materials and Methods: The study characterized the lyophilized crude venoms of Macrovipera lebetina lebetina and M. l. obtusa by FTIR spectroscopy coupled with attenuated total reflectance (ATR) method in the mid-infrared region and compared the spectra between the two subspecies. The band area and intensity values were calculated for comparison and wavenumbers were detected by automated peak picking. Additionally, the study analyzed the secondary structure of venom proteins by using the second derivative spectra. Results: The study detected fourteen major and minor peaks in absorbance spectra which were assigned to various biomolecules such as proteins, carbohydrates, and nucleic acids. Four major sub-bands were observed in the second derivative spectra of Amide I-II region indicating different protein secondary structures. It was observed that there are some quantitative differences and peak shifts between the spectra of venoms of two subspecies, indicating the alteration of biomolecules. Conclusion: To the best of our knowledge, this is the first report of the use of the FTIR-ATR spectroscopy method focusing solely on the characterization of crude snake venoms in literature, accompanied with detailed peak assignment and protein secondary structure analysis. As a preliminary reference study, the results showed the usefulness of FTIR-ATR spectroscopy for the physicochemical characterization of lyophilized snake venom.