1. Oligomerization of Sulfolobus solfataricus signature amidase is promoted by acidic pH and high temperature
- Author
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Laura Giangiacomo, Valerio Consalvi, Anna Scotto d'Abusco, Stefania Di Marco, Roberto Scandurra, Rita Casadio, Laura Politi, Valentina Calamia, Gianluca Tasco, Anna Giartosio, and Roberta Chiaraluce
- Subjects
Models, Molecular ,Article Subject ,Physiology ,Dimer ,Archaeal Proteins ,ved/biology.organism_classification_rank.species ,Molecular Sequence Data ,Microbiology ,Amidase ,law.invention ,Amidohydrolases ,Substrate Specificity ,hyperthermophile ,Gel permeation chromatography ,chemistry.chemical_compound ,Dynamic light scattering ,law ,amidase signature ,Histone octamer ,Amino Acid Sequence ,Ecology, Evolution, Behavior and Systematics ,Research Articles ,chemistry.chemical_classification ,amide metabolism ,ved/biology ,Sulfolobus solfataricus ,Temperature ,Hydrogen-Ion Concentration ,Amides ,QR1-502 ,Recombinant Proteins ,Molecular Weight ,Crystallography ,Enzyme ,chemistry ,Recombinant DNA ,Sequence Alignment - Abstract
The recombinant amidase from the hyperthermophylic archaeon Sulfolobus solfataricus (SSAM) a signature amidase, was cloned, purified and characterized. The enzyme is active on a large number of aliphatic and aromatic amides over the temperature range 60–95 °C and at pH values between 4.0 and 9.5, with an optimum at pH 5.0. The recombinant enzyme is in the form of a dimer of about 110 kD that reversibly associates into an octamer in a pH-dependent reaction. The pH dependence of the state of association was studied using gel permeation chromatography, analytical ultracentrifugation and dynamic light scattering techniques. At pH 7.0 all three techniques show the presence of two species, in about equal amounts, which is compatible with the existence of a dimeric and an octameric form. In decreasing pH, the dimers formed the octameric species and in increasing pH, the octameric species was converted to dimers. Above pH 8.0, only dimers were present, below pH 3.0 only octamers were present. The association of dimers into octamers decreased in non-polar solvents and increased with temperature. A mutant (Y41C) was obtained that did not show this behavior.
- Published
- 2005