6U0J

Crosslinked Crystal Structure of Malonyl-CoA Acyl Carrier Protein Transacylase, FabD, and Acyl Carrier Protein, AcpP

Summary for 6U0J

• Entry DOI: 10.2210/pdb6u0j/pdb
• Descriptor: Malonyl CoA-acyl carrier protein transacylase, Acyl carrier protein, 1,2-ETHANEDIOL, ... (6 entities in total)
• Functional Keywords: mat, at, transferase, acyl transferase, alpha-beta hydrolase fold, acpp, acp, cp
• Biological source: Escherichia coli (strain K12); More
• Total number of polymer chains: 2
• Total formula weight: 43216.71

Authors

Mindrebo, J.T.,Misson, L.,Davis, T.D.,Burkart, M.D.,Noel, J.P. (deposition date: 2019-08-14, release date: 2020-07-22, Last modification date: 2020-10-14)

Primary citation

Misson, L.E.,Mindrebo, J.T.,Davis, T.D.,Patel, A.,McCammon, J.A.,Noel, J.P.,Burkart, M.D.
Interfacial plasticity facilitates high reaction rate of E. coli FAS malonyl-CoA:ACP transacylase, FabD.
Proc.Natl.Acad.Sci.USA, 117:24224-24233, 2020

PubMed Abstract: Fatty acid synthases (FASs) and polyketide synthases (PKSs) iteratively elongate and often reduce two-carbon ketide units in de novo fatty acid and polyketide biosynthesis. Cycles of chain extensions in FAS and PKS are initiated by an acyltransferase (AT), which loads monomer units onto acyl carrier proteins (ACPs), small, flexible proteins that shuttle covalently linked intermediates between catalytic partners. Formation of productive ACP-AT interactions is required for catalysis and specificity within primary and secondary FAS and PKS pathways. Here, we use the FAS AT, FabD, and its cognate ACP, AcpP, to interrogate type II FAS ACP-AT interactions. We utilize a covalent crosslinking probe to trap transient interactions between AcpP and FabD to elucidate the X-ray crystal structure of a type II ACP-AT complex. Our structural data are supported using a combination of mutational, crosslinking, and kinetic analyses, and long-timescale molecular dynamics (MD) simulations. Together, these complementary approaches reveal key catalytic features of FAS ACP-AT interactions. These mechanistic inferences suggest that AcpP adopts multiple, productive conformations at the AT binding interface, allowing the complex to sustain high transacylation rates. Furthermore, MD simulations support rigid body subdomain motions within the FabD structure that may play a key role in AT activity and substrate selectivity.

PubMed: 32929027
DOI: 10.1073/pnas.2009805117

Experimental method

X-RAY DIFFRACTION (1.9 Å)