Premium
Effect of inhibitor binding to β subunits of F 1 ATPase on enzyme thermostability: a kinetic and FT‐IR spectroscopic analysis
Author(s) -
Lippe Giovanna,
Tanfani Fabio,
Di Pancrazio Francesca,
Contessi Stefania,
Bertoli Enrico,
Dabbeni-Sala Federica
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)00816-3
Subject(s) - thermostability , chemistry , enzyme , catalysis , nucleotide , atpase , thermal stability , kinetics , enzyme kinetics , stereochemistry , biochemistry , active site , organic chemistry , physics , quantum mechanics , gene
FT‐IR analysis shows that treatment of F 1 ATPase with the inhibitors DCCD and Nbf‐Cl, in the presence of saturating concentrations of ADP and AMP‐PNP and in the absence of Mg 2+ , does not modify the secondary structure of the enzyme, but significantly modifies its compactness and thermal stability, although to different extents. Nbf‐Cl causes a significant increase in stabilisation, in addition to that induced by nucleotides, while DCCD is less effective in this regard. Determination by HPLC of the exchange rate, in the absence of Mg 2+ , of tightly bound nucleotides of F 1 ATPase treated with the two inhibitors shows that DCCD does not significantly affect the exchange rate of ADP with AMP‐PNP and vice versa in catalytic and non‐catalytic tight sites, while Nbf‐Cl selectively reduces the enzyme's capacity to exchange ADP bound in the tight catalytic site. It is suggested that the effects of DCCD, unlike those of Nbf‐Cl, are closely related to the presence or absence of Mg 2+ .