title: Characterization of molecular interactions between ACP and halogenase domains in the Curacin A polyketide synthase.
abstract: Polyketide synthases (PKSs) and non-ribosomal peptide synthetases (NRPSs) are large multidomain proteins present in microorganisms that produce bioactive compounds. Curacin A is such a bioactive compound with potent anti-proliferative activity. During its biosynthesis the growing substrate is bound covalently to an acyl carrier protein (ACP) that is able to access catalytic sites of neighboring domains for chain elongation and modification. While ACP domains usually occur as monomers, the curacin A cluster codes for a triplet ACP (ACP(I)-ACP(II)-ACP(III)) within the CurA PKS module. We have determined the structure of the isolated holo-ACP(I) and show that the ACPs are independent of each other within this tridomain system. In addition, we have determined the structure of the 3-hydroxyl-3-methylglutaryl-loaded holo-ACP(I), which is the substrate for the unique halogenase (Hal) domain embedded within the CurA module. We have identified the interaction surface of both proteins using mutagenesis and MALDI-based identification of product formation. Amino acids affecting product formation are located on helices II and III of ACP(I) and form a contiguous surface. Since the CurA Hal accepts substrate only when presented by one of the ACPs within the ACP(I)-ACP(II)-ACP(III) tridomain, our data provide insight into the specificity of the chlorination reaction.
authors: Institute of Biophysical Chemistry, Goethe University Frankfurt and Center for Biomolecular Magnetic Resonance, Frankfurt am Main, Germany.
authors: Alena
authors: A
authors: Busche
authors: Daniel
authors: D
authors: Gottstein
authors: Christopher
authors: C
authors: Hein
authors: Nina
authors: N
authors: Ripin
authors: Irina
authors: I
authors: Pader
authors: Peter
authors: P
authors: Tufar
authors: Eli B
authors: EB
authors: Eisman
authors: Liangcai
authors: L
authors: Gu
authors: Christopher T
authors: CT
authors: Walsh
authors: David H
authors: DH
authors: Sherman
authors: Frank
authors: F
authors: Löhr
authors: Peter
authors: P
authors: Güntert
authors: Volker
authors: V
authors: Dötsch
mesh_terms: D000213:Acyl Carrier Protein / Q000737:chemistry* / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D000458:Cyanobacteria / Q000737:chemistry* / Q000378:metabolism; D003521:Cyclopropanes / Q000378:metabolism*; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D048630:Polyketide Synthases / Q000737:chemistry* / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D013844:Thiazoles / Q000378:metabolism*
chemical_list: D000213:Acyl Carrier Protein; D001426:Bacterial Proteins; D003521:Cyclopropanes; D013844:Thiazoles; C095843:curacin A; D048630:Polyketide Synthases