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Crystal structure of recombinant phosphoribosylpyrophosphate synthetase 2 from Thermus thermophilus HB27 complexed with ADP and sulfate ions
Author(s) -
Timofeev Vladimir I.,
Sinitsyna Ekaterina V.,
Kostromina Maria A.,
Muravieva Tatiana I.,
Makarov Dmitry A.,
Mikheeva Olga O.,
Kuranova Inna P.,
Esipov Roman S.
Publication year - 2017
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 37
ISSN - 2053-230X
DOI - 10.1107/s2053230x17007488
Subject(s) - thermus thermophilus , active site , allosteric regulation , chemistry , thermotoga maritima , stereochemistry , ammonium sulfate , multiple isomorphous replacement , enzyme , crystallography , biochemistry , escherichia coli , peptide sequence , chromatography , gene
Phosphoribosylpyrophosphate synthetase (PRPPS) from the thermophilic bacterial strain Thermus thermophilus HB27 catalyzes the synthesis of phosphoribosylpyrophosphate from ribose 5‐phosphate and ATP, and belongs to the class I PRPPSs. The three‐dimensional structure of the recombinant enzyme was solved at 2.2 Å resolution using crystals grown in microgravity from protein solution containing ATP, magnesium and sulfate ions. An ADP molecule was located in the active site of each subunit of the hexameric enzyme molecule and sulfate ions were located in both the active and allosteric sites. It was found that the catalytic loop that restricts the active‐site area and is usually missing from the electron‐density map of class I PRPPSs adopts different conformations in three independent subunits in T. thermophilus PRPPS. A closed conformation of the active site was found in one of subunits where the highly ordered catalytic β‐hairpin delivers the Lys and Arg residues that are essential for activity directly to the ADP molecule, which occupies the ATP‐binding site. A comparison of the conformations of the catalytic loop in the three independent subunits reveals a possible mode of transition from the open to the closed state of the active site during the course of the catalyzed reaction.