Substrate Binding Induces Domain Movements in Orotidine 5'-Monophosphate Decarboxylase

TY - JOUR

T1 - Substrate Binding Induces Domain Movements in Orotidine 5'-Monophosphate Decarboxylase

AU - Harris, Pernille Hanne

AU - Poulsen, Jens-Christian Navarro

AU - Jensen, Kaj Frank

AU - Larsen, Sine

N1 - Author Keywords: domain movements; orotidine 5'-monophosphate decarboxylase; substrate binding; twinning; catalysis

PY - 2002

Y1 - 2002

N2 - Orotidine 5'-monophosphate decarboxylase (ODCase) catalyses the decarboxylation of orotidine 5'-monophosphate to uridine 5'-monophosphate (UMP). We have earlier determined the structure of ODCase from Escherichia coli complexed with the inhibitor 1-(5'-phospho-ß- -ribofuranosyl)barbituric acid (BMP); here we present the 2.5 Å structure of the uncomplexed apo enzyme, determined from twinned crystals. A structural analysis and comparison of the two structures of the E. coli enzyme show that binding of the inhibitor is accompanied by significant domain movements of approximately 12° around a hinge that crosses the active site. Hence, the ODCase dimer, which contains two active sites, may be divided in three domains: a central domain that is fixed, and two lids which independently move 12° upon binding. Corresponding analyses, presented herein, of the two Saccharomyces cerevisiae ODCase structures (with and without BMP) and the Methanobacterium thermoautotrophicum ODCase structures (with and without 6-aza UMP) show very similar, but somewhat smaller domain movements. The domain movements seem to be initiated by the phosphoryl binding to the enzyme and can explain why the binding of the phosphoryl group is essential for the catalytic function.

AB - Orotidine 5'-monophosphate decarboxylase (ODCase) catalyses the decarboxylation of orotidine 5'-monophosphate to uridine 5'-monophosphate (UMP). We have earlier determined the structure of ODCase from Escherichia coli complexed with the inhibitor 1-(5'-phospho-ß- -ribofuranosyl)barbituric acid (BMP); here we present the 2.5 Å structure of the uncomplexed apo enzyme, determined from twinned crystals. A structural analysis and comparison of the two structures of the E. coli enzyme show that binding of the inhibitor is accompanied by significant domain movements of approximately 12° around a hinge that crosses the active site. Hence, the ODCase dimer, which contains two active sites, may be divided in three domains: a central domain that is fixed, and two lids which independently move 12° upon binding. Corresponding analyses, presented herein, of the two Saccharomyces cerevisiae ODCase structures (with and without BMP) and the Methanobacterium thermoautotrophicum ODCase structures (with and without 6-aza UMP) show very similar, but somewhat smaller domain movements. The domain movements seem to be initiated by the phosphoryl binding to the enzyme and can explain why the binding of the phosphoryl group is essential for the catalytic function.

U2 - 10.1016/S0022-2836(02)00200-0

DO - 10.1016/S0022-2836(02)00200-0

M3 - Journal article

SN - 0022-2836

VL - 318

SP - 1019

EP - 1029

JO - Journal of Molecular Biology

JF - Journal of Molecular Biology

IS - 4

ER -