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Influence of ADP, AMP‐PNP and of depletion of nucleotides on the structural properties of F 1 ATPase: a Fourier transform infrared spectroscopic study
Author(s) -
Lippe Giovanna,
Di Pancrazio Francesca,
Dabbeni-Sala Federica,
Bertoli Enrico,
Tanfani Fabio
Publication year - 1995
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 - 10.1016/0014-5793(95)01022-7
Subject(s) - nucleotide , atpase , enzyme , chemistry , destabilisation , glycerol , stereochemistry , biochemistry , biophysics , biology , psychology , social psychology , gene
Mitochondrial F 1 ATPase from beef heart was treated with different buffers in order to modulate the nucleotide content of the enzyme and then analysed by FT‐IR spectroscopy. Treatment of F 1 ATPase with a buffer lacking nucleotides and glycerol led to the formation of two fractions consisting of an inactive aggregated enzyme deprived almost completely of bound nucleotides and of an active enzyme containing ATP only in the tight sites and having a structure largely accessible to the solvent and a low thermal stability. Treatment of F 1 ATPase with saturating ADP, which induced the hysteretic inhibition during turnover, or AMP‐PNP did not affect remarkably the secondary structure of the enzyme complex but significantly increased its compactness and thermal stability. It was hypothesised that the formation of the inactive aggregated enzyme was mainly due to the destabilisation of the α‐subunits of F 1 ATPase and that the induction of the hysteretic inhibition is related to a particular conformation of the enzyme, which during turnover becomes unable to sustain catalysis.