Crystal structure of Pyrococcus furiosus phosphoglucose isomerase. Implications for substrate binding and catalysis.
Phosphoglucose isomerase (PGI) catalyzes the reversible isomerization between d-fructose 6-phosphate and d-glucose 6-phosphate as part of the glycolytic pathway. PGI from the Archaea Pyrococcus furiosus (Pfu) was crystallized, and its structure was determined by x-ray diffraction to a 2-A resolution. Structural comparison of this archaeal PGI with the previously solved structures of bacterial and eukaryotic PGIs reveals a completely different structure. Each subunit of the homodimeric Pfu PGI consists of a cupin domain, for which the overall structure is similar to other cupin domain-containing proteins, and includes a conserved transition metal-binding site. Biochemical data on the recombinant enzyme suggests that Fe2+ is bound to Pfu PGI. However, as catalytic activity is not strongly influenced either by the replacement of Fe2+ by a range of transition metals or by the presence or absence of the bound metal ion, we suggest that the metal may not be directly involved in catalysis but rather may be implicated in substrate recognition.
Berrisford
John M
JM
Department of Molecular Biology and Biotechnology, Krebs Institute for Biomolecular Research, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom.
Akerboom
Jasper
J
Turnbull
Andrew P
AP
de Geus
Daniel
D
Sedelnikova
Svetlana E
SE
Staton
Ian
I
McLeod
Cameron W
CW
Verhees
Corne H
CH
van der Oost
John
J
Rice
David W
DW
Baker
Patrick J
PJ
D000595:Amino Acid Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D019281:Dimerization; D005636:Fructosephosphates / Q000737:chemistry; D019298:Glucose-6-Phosphate / Q000737:chemistry; D005956:Glucose-6-Phosphate Isomerase / Q000737:chemistry*; D007477:Ions; D007501:Iron / Q000737:chemistry; D008670:Metals / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D020027:Pyrococcus furiosus / Q000201:enzymology*; D012645:Selenomethionine / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013696:Temperature; D014961:X-Ray Diffraction
D005636:Fructosephosphates; D007477:Ions; D008670:Metals; D019298:Glucose-6-Phosphate; C027618:fructose-6-phosphate; D012645:Selenomethionine; D007501:Iron; D005956:Glucose-6-Phosphate Isomerase