Biomaterial Database

Utilization of enzymatically phosphopantetheinylated acyl carrier proteins and acetyl-acyl carrier proteins by the actinorhodin polyketide synthase. 1997

C W Carreras, and A M Gehring, and C T Walsh, and C Khosla

Department of Chemical Engineering, Stanford University, Stanford, California 94305-5025, USA.

The functional reconstitution of two purified proteins of an aromatic polyketide synthase pathway, the acyl carrier protein (ACP) and holo-ACP synthase (ACPS), is described. Holo-ACPs were enzymatically synthesized from coenzyme A and apo-ACPs using Escherichia coli ACPS. Frenolicin and granaticin holo-ACPs formed in this manner were shown to be fully functional together with the other components of the minimal actinorhodin polyketide synthase (act PKS), resulting in synthesis of the same aromatic polyketides as those formed by the act PKS in vivo. ACPS also catalyzed the transfer of acetyl-, propionyl-, butyryl-, benzoyl-, phenylacetyl-, and malonylphosphopantetheines to apo-ACPs from their corresponding coenzyme As, as detected by electrophoresis and/or mass spectrometry. A steady state kinetic study showed that acetyl-coenzyme A is as efficient an ACPS substrate as coenzyme A, with kcat and Km values of 20 min-1 and 25 microM, respectively. In contrast to acetyl-coenzyme A, enzymatically synthesized acetyl-ACPs were shown to be efficient substrates for the act PKS, indicating that acetyl-ACP is a chemically competent intermediate of aromatic polyketide biosynthesis. Together, these methods provide a valuable tool for dissecting the mechanisms and molecular recognition features of polyketide biosynthesis.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008956	Models, Chemical	Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.	Chemical Models,Chemical Model,Model, Chemical
D010727	Phosphoric Diester Hydrolases	A class of enzymes that catalyze the hydrolysis of one of the two ester bonds in a phosphodiester compound. EC 3.1.4.	Phosphodiesterase,Phosphodiesterases,Hydrolases, Phosphoric Diester
D002384	Catalysis	The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.	Catalyses
D000213	Acyl Carrier Protein	Consists of a polypeptide chain and 4'-phosphopantetheine linked to a serine residue by a phosphodiester bond. Acyl groups are bound as thiol esters to the pantothenyl group. Acyl carrier protein is involved in every step of fatty acid synthesis by the cytoplasmic system.	Myristoyl-ACP,Carrier Protein, Acyl,Myristoyl ACP,Protein, Acyl Carrier
D000217	Acyltransferases	Enzymes from the transferase class that catalyze the transfer of acyl groups from donor to acceptor, forming either esters or amides. (From Enzyme Nomenclature 1992) EC 2.3.	Acyltransferase
D001426	Bacterial Proteins	Proteins found in any species of bacterium.	Bacterial Gene Products,Bacterial Gene Proteins,Gene Products, Bacterial,Bacterial Gene Product,Bacterial Gene Protein,Bacterial Protein,Gene Product, Bacterial,Gene Protein, Bacterial,Gene Proteins, Bacterial,Protein, Bacterial,Proteins, Bacterial
D013302	Streptomyces	A genus of bacteria that form a nonfragmented aerial mycelium. Many species have been identified with some being pathogenic. This genus is responsible for producing a majority of the ANTI-BACTERIAL AGENTS of practical value.
D048630	Polyketide Synthases	Large enzyme complexes composed of a number of component enzymes that are found in STREPTOMYCES which biosynthesize MACROLIDES and other polyketides.	Polyketide Synthase,6-Deoxyerythronolide-B Synthase,Epothilone Polyketide Synthase,Erythromycin Polyketide Synthase,Griseusin Polyketide Synthase,Niddamycin Polyketide Synthase,Polyketide Synthase L1,Polyketide Synthase WA,Rifamycin Polyketide Synthase,Sterigmatocystin Polyketide Synthase,Type I Polyketide Synthase,Type II Polyketide Beta-Ketoacyl Synthase,Urdamycin Polyketide Synthase,WdPKS1 Protein,WhiE Polyketide Synthase,6 Deoxyerythronolide B Synthase,Polyketide Synthase, Epothilone,Polyketide Synthase, Erythromycin,Polyketide Synthase, Griseusin,Polyketide Synthase, Niddamycin,Polyketide Synthase, Rifamycin,Polyketide Synthase, Sterigmatocystin,Polyketide Synthase, Urdamycin,Polyketide Synthase, WhiE,Protein, WdPKS1,Synthase L1, Polyketide,Synthase WA, Polyketide,Synthase, 6-Deoxyerythronolide-B,Synthase, Epothilone Polyketide,Synthase, Erythromycin Polyketide,Synthase, Griseusin Polyketide,Synthase, Niddamycin Polyketide,Synthase, Polyketide,Synthase, Rifamycin Polyketide,Synthase, Sterigmatocystin Polyketide,Synthase, Urdamycin Polyketide,Synthase, WhiE Polyketide,Synthases, Polyketide,Type II Polyketide Beta Ketoacyl Synthase
D017855	Transferases (Other Substituted Phosphate Groups)	A class of enzymes that transfers substituted phosphate groups. EC 2.7.8.	Phosphotransferases (Other Substituted Phosphate Groups)