Localization of the site for the nucleotide effectors of Escherichia coli carbamoyl phosphate synthetase using site‐directed mutagenesis

FEBS Letters

Rubio, Vicente¹  Mora, Paz²  Fresquet, Vicente²  Cervera, Javier² 

[1] Instituto de Biomedicina de Valencia (CSIC), C/ Jaime Roig 11, Valencia 46010, Spain;Instituto de Investigaciones Citológicas (FVIB), C/ Amadeo de Saboya 4, Valencia 46010, Spain

关键词: Carbamoyl phosphate synthetase;    Allosteric regulation;    Site-directed mutagenesis;    Arginine synthesis;    Pyrimidine synthesis;    carB;    CPS;    carbamoyl phosphate synthetase;    EDTA;    ethylene diamine tetraacetic acid;    PAGE;    polyacrylamide gel electrophoresis;    SDS;    sodium dodecyl sulfate;   

DOI  :  10.1016/S0014-5793(99)00197-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Replacement by alanine of Ser-948, Thr-974 and Lys-954 of Escherichia coli carbamoyl phosphate synthetase (CPS) shows that these residues are involved in binding the allosteric inhibitor UMP and the activator IMP. The mutant CPSs are active in vivo and in vitro and exhibit normal activation by ornithine, but the modulation by both UMP and IMP is either lost or diminished. The results demonstrate that the sites for UMP and IMP overlap and that the activator ornithine binds elsewhere. Since the mutated residues were found in the crystal structure of CPS near a bound phosphate, Ser-948, Thr-974 and Lys-954 bind the phosphate moiety of UMP and IMP.

【 授权许可】

Unknown