title: Whole-cell biocatalytic production of variously substituted β-aryl- and β-heteroaryl-β-amino acids.
abstract: Biologically-active β-peptides and pharmaceuticals that contain key β-amino acids are emerging as target therapeutics; thus, synthetic strategies to make substituted, enantiopure β-amino acids are increasing. Here, we use whole-cell Escherichia coli (OD600 ∼ 35) engineered to express a Pantoea agglomerans phenylalanine aminomutase (PaPAM) biocatalyst. In either 5 mL, 100mL, or 1L of M9 minimal medium containing α-phenylalanine (20mM), the cells produced ∼ 1.4 mg mL(-1) of β-phenylalanine in each volume. Representative pilot-scale 5-mL cultures, fermentation reactions converted 18 variously substituted α-arylalanines to their (S)-β-aryl-β-amino acids in vivo and were not toxic to cells at mid- to late-stage growth. The β-aryl-β-amino acids made ranged from 0.043 mg (p-nitro-β-phenylalanine, 4% converted yield) to 1.2mg (m-bromo-β-phenylalanine, 96% converted yield) over 6h in 5 mL. The substituted β-amino acids made herein can be used in redox and Stille-coupling reactions to make synthetic building blocks, or as bioisosteres in drug design.
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Nishanka Dilini
authors.initials: ND
authors.lastname: Ratnayake
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA; Lake Superior State University, Sault Ste. Marie, MI 49783, USA.
authors.forename: Chelsea
authors.initials: C
authors.lastname: Theisen
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Tyler
authors.initials: T
authors.lastname: Walter
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA. Electronic address: walker@chemistry.msu.edu.
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Walker
mesh_terms: D055162:Biocatalysis; D002470:Cell Survival; D002849:Chromatography, Gas; D002934:Cinnamates / Q000378:metabolism; D015195:Drug Design; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D019751:Intramolecular Transferases / Q000096:biosynthesis / Q000235:genetics; D010084:Oxidation-Reduction; D020636:Pantoea / Q000201:enzymology; D010649:Phenylalanine / Q000096:biosynthesis* / Q000737:chemistry; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D002934:Cinnamates; D010649:Phenylalanine; D019751:Intramolecular Transferases
keywords: Aminomutase; Batch-reaction sustainability; Chiral amine; Whole-cell biocatalysis; β-Amino acids