MANDELATE RACEMASE AND MUCONATE LACTONIZING ENZYME ARE MECHANISTICALLY DISTINCT AND STRUCTURALLY HOMOLOGOUS
MANDELATE RACEMASE AND MUCONATE LACTONIZING ENZYME ARE MECHANISTICALLY DISTINCT AND STRUCTURALLY HOMOLOGOUS
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DOI：
10.1038/347692a0
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发表时间：
1990-10-18
期刊：
影响因子：
64.8
通讯作者：
PETSKO, GA
中科院分区：
文献类型：
--
作者：
NEIDHART, DJ;KENYON, GL;PETSKO, GA
MANDELATE racemase (MR) and muconate lactonizing enzyme (MLE) catalyse separate and mechanistically distinct reactions necessary for the catabolism of aromatic acids byPseudomonas putida1–3. The X-ray crystal structure of MR, solved at 2.5 Å resolution, reveals that the secondary, tertiary and quaternary structures of MR and MLE4are remarkably similar; also, MR and MLE are about 26% identical in primary structure5. However, MR has no detectable MLE activity and vice versa. Thus, MR and MLE constitute the first example of enzymes that catalyse different reactions, as opposed to mechanistically identical reactions on different substrates, yet possess sufficient structural and sequence identity that they are likely to have evolved from a common ancestor. The discovery that MR and MLE catalyse different reactions but share a common structural framework has broad implications for the natural evolution of enzymes and metabolic pathways, as well as for the rational modification of enzyme activities.
