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Hydrophobic Interactions and Ionic Networks Play an Important Role in Thermal Stability and Denaturation Mechanism of the Porcine Odorant-binding Protein by Olesya V. Stepanenko; Anna Marabotti; Irina M. Kuznetsova; Konstantin K. Turoverov; Carlo Fini; Antonio Varriale; Maria Staiano; Mose' Rossi; Sabato D'Auria is a Biochemistry, Genetics and Molecular Biology article available to read on EtoBox.

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## Abstract Despite the fact that the porcine odorant‐binding protein (pOBP) possesses a single tryptophan residue (Trp 16) that is characterized by a high density microenvironment (80 atoms in a sphere with radius 7 Å) with only one polar group (Lys 120) and three bound water molecules, pOBP displayed a red shifted fluorescence emission spectrum (λ~max~ = 340 nm). The protein unfolding in 5__M__ GdnHCl was accompanied by the red shift of the fluorescence emission spectrum (λ~max~ = 353 nm), by the increase of fluorescence quantum yield, and by the decrease of lifetime of the excited state (from 4.25 ns in native state to 3.15 ns in the presence of 5__M__ GdnHCl). Taken together these data indicate the existence of an exciplex complex (Trp 16 with Lys 120 and/or with bound molecules of water) in the protein native state. Heat‐induced denaturation of pOBP resulted in significant red shifts of the fluorescence emission spectra: the value of the ratio (__I__~320~/I~365~) upon excitation at λ~ex~ = 297 nm (parameter A) decreases from 1.07 to 0.64 passing from 60 to 85°C, and the calculated midpoint of transition was centered at 70°C. Interestingly, even at higher temperature, the value

Who reads Hydrophobic Interactions and Ionic Networks Play an Important Role in Thermal Stability and Denaturation Mechanism of the Porcine Odorant-binding Protein?

Author

Olesya V. Stepanenko; Anna Marabotti; Irina M. Kuznetsova; Konstantin K. Turoverov; Carlo Fini; Antonio Varriale; Maria Staiano; Mose' Rossi; Sabato D'Auria

Publisher

John Wiley and Sons; Wiley (John Wiley & Sons); Wiley-Liss Inc; Wiley (ISSN 0887-3585)

Published

2007

Language

EN

Field

Biochemistry, Genetics and Molecular Biology (Life Sciences)