FEBS Letters | |
Modification of a catalytically important residue of indoleglycerol‐phosphate synthase from Escherichia coli | |
Kirschner, Kasper1  Eberhard, Marc1  | |
[1] Biozentrum der Universität, Abteilung Biophysikalische Chemie, Klingelbergstrasse 70, CH-4056 Basel, Switzerland | |
关键词: Indoleglycerol-phosphate synthase; Catalytic mechanism; Site-directed mutagenesis; (Escherichia coli); CdRP; 1-(2-carboxyphenylamino)-1-deoxyribulose 5-phosphate; DTE; 1; 4-dithiothreitol; IGP; indoleglycerol phosphate; PRA; N-(5′-phosphoribosyl-1-)anthranilate; PMSF; phenylmethylsulfonyl fluoride; rCdRP; reduced CdRP; | |
DOI : 10.1016/0014-5793(89)80225-X | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
The active-site residues of indoleglycerol-phosphate synthase from Escherichia coli were tentatively localized by comparing crystallographic data with the amino acid identities among the known indoleglycerol-phosphate synthase sequences. To test the validity of the resulting model of catalysis one of the residues in the presumptive active site, Lys 55, was changed to serine using oligonucleotide-directed mutagenesis. The specificity constant k cat/K m of the mutant is 3 × 104-times lower than that of the wild-type enzyme, due to a 60-fold decrease in k cat and a 450-fold increase in K m. This finding shows that Lys 55 is important for both catalysis and substrate binding.
【 授权许可】
Unknown
【 预 览 】
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RO201912020291773ZK.pdf | 310KB | download |