Structural and mutational analysis of substrate complexation by anthranilate phosphoribosyltransferase from Sulfolobus solfataricus.
The metabolic synthesis and degradation of essential nucleotide compounds are primarily carried out by phosphoribosyltransferases (PRT) and nucleoside phosphorylases (NP), respectively. Despite the resemblance of their reactions, five classes of PRTs and NPs exist, where anthranilate PRT (AnPRT) constitutes the only evolutionary link between synthesis and degradation processes. We have characterized the active site of dimeric AnPRT from Sulfolobus solfataricus by elucidating crystal structures of the wild-type enzyme complexed to its two natural substrates anthranilate and 5-phosphoribosyl-1-pyrophosphate/Mg(2+). These bind into two different domains within each protomer and are brought together during catalysis by rotational domain motions as shown by small angle x-ray scattering data. Steady-state kinetics of mutated AnPRT variants address the role of active site residues in binding and catalysis. Results allow the comparative analysis of PRT and pyrimidine NP families and expose related structural motifs involved in nucleotide/nucleoside recognition by these enzyme families.
Marino
Marco
M
Division of Structural Biology, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.
Deuss
Miriam
M
Institut für Biophysik und physikalische Biochemie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany; Institut für Biochemie, Universität zu Köln, Otto-Fischer-Strasse 12-14, D-50674 Köln, Germany.
Svergun
Dmitri I
DI
European Molecular Biology Laboratory, Hamburg Outstation, c/o DESY, Notkestrasse 85, D-22603 Hamburg, Germany; Institute of Crystallography, Russian Academy of Sciences, Leninsky pr. 59, 117333 Moscow, Russia.
Konarev
Petr V
PV
European Molecular Biology Laboratory, Hamburg Outstation, c/o DESY, Notkestrasse 85, D-22603 Hamburg, Germany; Institute of Crystallography, Russian Academy of Sciences, Leninsky pr. 59, 117333 Moscow, Russia.
Sterner
Reinhard
R
Institut für Biophysik und physikalische Biochemie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany; Institut für Biochemie, Universität zu Köln, Otto-Fischer-Strasse 12-14, D-50674 Köln, Germany.
Mayans
Olga
O
Division of Structural Biology, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland. Electronic address: Olga.Mayans@unibas.ch.
D000595:Amino Acid Sequence; D000818:Animals; D000877:Anthranilate Phosphoribosyltransferase / Q000737:chemistry* / Q000235:genetics*; D002417:Cattle; D018360:Crystallography, X-Ray; D004252:DNA Mutational Analysis / Q000379:methods*; D019281:Dimerization; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D048229:Sulfolobus solfataricus / Q000201:enzymology*
D000877:Anthranilate Phosphoribosyltransferase