6oz1
From Proteopedia
Crystal structure of the adenylation (A) domain of the carboxylate reductase (CAR) GR01_22995 from Mycobacterium chelonae
Structural highlights
FunctionA0A0E3TT64_MYCCH Catalyzes the ATP- and NADPH-dependent reduction of carboxylic acids to the corresponding aldehydes.[HAMAP-Rule:MF_02247] Publication Abstract from PubMedProduction of platform chemicals from renewable feedstocks is becoming increasingly important due to concerns on environmental contamination, climate change, and depletion of fossil fuels. Adipic acid (AA), 6-aminocaproic acid (6-ACA) and 1,6-hexamethylenediamine (HMD) are key precursors for nylon synthesis, which are currently produced primarily from petroleum-based feedstocks. In recent years, the biosynthesis of adipic acid from renewable feedstocks has been demonstrated using both bacterial and yeast cells. Here we report the biocatalytic conversion/transformation of AA to 6-ACA and HMD by carboxylic acid reductases (CARs) and transaminases (TAs), which involves two rounds (cascades) of reduction/amination reactions (AA --> 6-ACA --> HMD). Using purified wild type CARs and TAs supplemented with cofactor regenerating systems for ATP, NADPH, and amine donor, we established a one-pot enzyme cascade catalyzing up to 95% conversion of AA to 6-ACA. To increase the cascade activity for the transformation of 6-ACA to HMD, we determined the crystal structure of the CAR substrate-binding domain in complex with AMP and succinate and engineered three mutant CARs with enhanced activity against 6-ACA. In combination with TAs, the CAR L342E protein showed 50-75% conversion of 6-ACA to HMD. For the transformation of AA to HMD (via 6-ACA), the wild type CAR was combined with the L342E variant and two different TAs resulting in up to 30% conversion to HMD and 70% to 6-ACA. Our results highlight the suitability of CARs and TAs for several rounds of reduction/amination reactions in one-pot cascade systems and their potential for the biobased synthesis of terminal amines. One-Pot Biocatalytic Transformation of Adipic Acid to 6-Aminocaproic Acid and 1,6-Hexamethylenediamine Using Carboxylic Acid Reductases and Transaminases.,Fedorchuk TP, Khusnutdinova AN, Evdokimova E, Flick R, Di Leo R, Stogios P, Savchenko A, Yakunin AF J Am Chem Soc. 2020 Jan 15;142(2):1038-1048. doi: 10.1021/jacs.9b11761. Epub 2020, Jan 7. PMID:31886667[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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