A Cell Free System for the Biocatalytic Production of Semisynthetic Penicillins
Yingyi Huang, Tymesha Bovell, Huong Trinh, Claudia Harnish-Meyer, Chas Smith, Guillermo Rodriguez
Department of Chemistry & Biochemistry
Faculty Supervisor: George Gassner
Despite the global importance of penicillins to public health, the manufacture and distribution of these antibiotics is deprioritized by pharmaceutical companies driven by more financially rewarding exploits and the rate of manufacture of penicillins fails to meet annual demands. This results in penicillin shortages that are responsible for hundreds of thousands of preventable deaths annually from common bacterial infections. In addition, current industrial synthesis of semisynthetic penicillins relies on organic solvents and coupling strategies that are environmentally harmful. As an alternative approach our laboratory is developing a cell-free biocatalytic pathway for the cost effective green-chemical synthesis of penicillins beginning from styrene and alcohol substrates as chemical synthons. In the first stage of this pathway, styrene monooxygenase (SMO) and styrene oxide isomerase (SOI) are joined in the oxidation of styrenes, and phenylethanol dehydrogenase (PEDH) applied in the oxidation of alcohols to aldehydes. Aldehydes produced through these convergent pathways are then used in the production of thioesters. The thioesters are then used as co-substrates with 6-aminopenicillanic in the attachment of penicillin sidechains through the sequential activities of an acylating aldehyde dehydrogenase (AAD) and isopenicillanic acid N-acyl transferase (IAT). Structural and mechanistic features of these engineered enzymes and pathway steps will be presented.