Fourier-transform infrared spectroscopy study of dehydrated lipases from Candida antarctica B and Pseudomonas cepacia
✍ Scribed by Giuseppe Vecchio; Francesca Zambianchi; Paola Zacchetti; Francesco Secundo; Giacomo Carrea
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 122 KB
- Volume
- 64
- Category
- Article
- ISSN
- 0006-3592
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✦ Synopsis
Fourier-transform infrared (FT-IR) spectroscopy was employed to investigate potential lyophilization-induced changes in the secondary structure of lipases from Candida antarctica B and Pseudomonas cepacia. The secondary structure elements were deter- mined by curve fitting of the amide III bands of the two lipases in the lyophilized state in KBr pellets and in solution. It was found that lyophilization decreased the ␣-helix and increased the -sheet content. However, FT-IR analysis of crosslinked enzyme crystals of Pseudomonas cepacia lipase also indicated an increase in the -sheet content, which appears despite the fact that the enzyme, being in the crystallized state, should possess native conformation. This result partially questions the suitability of FT-IR for analysis of the structure of solid proteins, at least as far as the -sheet content is concerned, because it is possible that the method overestimates the -sheets by measuring other hydrogen-bonded nonperiodic intermolecular structures. No significant modification was observed when lipase from Pseudomonas cepacia was lyophilized in the presence of methoxypoly(ethylene glycol).