RESUMO
The addition of water to non-activated carbon-carbon double bonds catalyzed by fatty acid hydratases (FAHYs) allows for highly regio- and stereoselective oxyfunctionalization of renewable oil feedstock. So far, the applicability of FAHYs has been limited to free fatty acids, mainly owing to the requirement of a carboxylate function for substrate recognition and binding. Herein, we describe for the first time the hydration of oleic acid (OA) derivatives lacking this free carboxylate by the oleate hydratase from Elizabethkingia meningoseptica (OhyA). Molecular docking of OA to the OhyA 3D-structure and a sequence alignment uncovered conserved amino acid residues at the entrance of the substrate channel as target positions for enzyme engineering. Exchange of selected amino acids gave rise to OhyA variants which showed up to an 18-fold improved conversion of OA derivatives, while retaining the excellent regio- and stereoselectivity in the olefin hydration reaction.
Assuntos
Ácidos Graxos/metabolismo , Flavobacteriaceae/enzimologia , Hidroliases/química , Hidroliases/metabolismo , Ácido Oleico/química , Ácido Oleico/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Catálise , Modelos Moleculares , Simulação de Acoplamento Molecular , Conformação Proteica , Estereoisomerismo , Especificidade por SubstratoRESUMO
FtsEX is a member of a small subclass of ABC transporters that uses mechano-transmission to perform work in the periplasm. FtsEX controls periplasmic peptidoglycan (PG) hydrolase activities in many Gram negative and positive organisms to ensure the safe separation of daughter cells during division. In these organisms FtsEX localizes to the Z ring and uses its ATPase activity to regulate its periplasmic effectors. In Escherichia coli, FtsEX also participates in building the divisome and coordinates PG synthesis with PG hydrolysis. This review discusses studies that are beginning to elucidate the mechanisms of FtsEX's various roles in cell division.