5VBX

Crystal structure of holo-[acyl-carrier-protein] synthase (AcpS) from Escherichia coli

Summary for 5VBX

• Entry DOI: 10.2210/pdb5vbx/pdb
• Descriptor: Holo-[acyl-carrier-protein] synthase, 1,2-ETHANEDIOL, SODIUM ION, ... (4 entities in total)
• Functional Keywords: trimer, transferase
• Biological source: Escherichia coli (strain K12)
• Total number of polymer chains: 3
• Total formula weight: 42926.35

Authors

Marcella, A.M.,Barb, A.W. (deposition date: 2017-03-30, release date: 2017-11-01, Last modification date: 2023-10-04)

Primary citation

Marcella, A.M.,Culbertson, S.J.,Shogren-Knaak, M.A.,Barb, A.W.
Structure, High Affinity, and Negative Cooperativity of the Escherichia coli Holo-(Acyl Carrier Protein):Holo-(Acyl Carrier Protein) Synthase Complex.
J. Mol. Biol., 429:3763-3775, 2017

PubMed Abstract: The Escherichia coli holo-(acyl carrier protein) synthase (ACPS) catalyzes the coenzyme A-dependent activation of apo-ACPP to generate holo-(acyl carrier protein) (holo-ACPP) in an early step of fatty acid biosynthesis. E. coli ACPS is sufficiently different from the human fatty acid synthase to justify the development of novel ACPS-targeting antibiotics. Models of E. coli ACPS in unliganded and holo-ACPP-bound forms solved by X-ray crystallography to 2.05and 4.10Å, respectively, revealed that ACPS bound three product holo-ACPP molecules to form a 3:3 hexamer. Solution NMR spectroscopy experiments validated the ACPS binding interface on holo-ACPP using chemical shift perturbations and by determining the relative orientation of holo-ACPP to ACPS by fitting residual dipolar couplings. The binding interface is organized to arrange contacts between positively charged ACPS residues and the holo-ACPP phosphopantetheine moiety, indicating product contains more stabilizing interactions than expected in the enzyme:substrate complex. Indeed, holo-ACPP bound the enzyme with greater affinity than the substrate, apo-ACPP, and with negative cooperativity. The first equivalent of holo-ACPP bound with a K=62±13nM, followed by the binding of two more equivalents of holo-ACPP with K=1.2±0.2μM. Cooperativity was not observed for apo-ACPP which bound with K=2.4±0.1μM. Strong product binding and high levels of holo-ACPP in the cell identify a potential regulatory role of ACPS in fatty acid biosynthesis.

PubMed: 29054754
DOI: 10.1016/j.jmb.2017.10.015

Experimental method

X-RAY DIFFRACTION (2.05 Å)