Abstract Nat/Ivy is a diverse and ubiquitous CoA‐binding evolutionary lineage that catalyzes acyltransferase reactions, primarily converting thioesters into amides. At the heart of the Nat/Ivy fold is a phosphate‐binding loop that bears a striking resemblance to that of P‐loop NTPases—both are extended, glycine‐rich loops situated between a β‐strand and an α‐helix. Nat/Ivy, therefore, represents an intriguing intersection between thioester chemistry, a putative primitive energy currency, and an ancient mode of phospho‐ligand binding. Current evidence suggests that Nat/Ivy emerged independently of other cofactor‐utilizing enzymes, and that the observed structural similarity—particularly of the cofactor binding site—is the product of shared constraints instead of shared ancestry. The reliance of Nat/Ivy on a β‐α‐β motif for CoA‐binding highlights the extent to which this simple structural motif may have been a fundamental evolutionary “nucleus” around which modern cofactor‐binding domains condensed, as has been suggested for HUP domains, Rossmanns, and P‐loop NTPases. Finally, by dissecting the patterns of conserved interactions between Nat/Ivy families and CoA, the coevolution of the enzyme and the cofactor was analyzed. As with the Rossmann, it appears that the pyrophosphate moiety at the center of the cofactor predates the enzyme, suggesting that Nat/Ivy emerged sometime after the metabolite dephospho‐CoA.
more »
« less
Rapid-reaction kinetics of the butyryl-CoA dehydrogenase component of the electron-bifurcating crotonyl-CoA-dependent NADH:ferredoxin oxidoreductase from Megasphaera elsdenii
- Award ID(s):
- 2101672
- PAR ID:
- 10625842
- Publisher / Repository:
- ASBMB
- Date Published:
- Journal Name:
- Journal of Biological Chemistry
- Volume:
- 299
- Issue:
- 7
- ISSN:
- 0021-9258
- Page Range / eLocation ID:
- 104853
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Crystal structure of the 4-hydroxybutyryl-CoA synthetase (ADP-forming) from nitrosopumilus maritimusAbstract The 3-hydroxypropionate/4-hydroxybutyrate (3HP/4HB) cycle from ammonia-oxidizing Thaumarchaeota is currently considered the most energy-efficient aerobic carbon fixation pathway. TheNitrosopumilus maritimus4-hydroxybutyryl-CoA synthetase (ADP-forming; Nmar_0206) represents one of several enzymes from this cycle that exhibit increased efficiency over crenarchaeal counterparts. This enzyme reduces energy requirements on the cell, reflecting thaumarchaeal success in adapting to low-nutrient environments. Here we show the structure of Nmar_0206 fromNitrosopumilus maritimusSCM1, which reveals a highly conserved interdomain linker loop between the CoA-binding and ATP-grasp domains. Phylogenetic analysis suggests the widespread prevalence of this loop and highlights both its underrepresentation within the PDB and structural importance within the (ATP-forming) acyl-CoA synthetase (ACD) superfamily. This linker is shown to have a possible influence on conserved interface interactions between domains, thereby influencing homodimer stability. These results provide a structural basis for the energy efficiency of this key enzyme in the modified 3HP/4HB cycle of Thaumarchaeota.more » « less
-
ABSTRACT Diacylglycerol O‐acyltransferase 1 (DGAT1) is an integral membrane protein that uses acyl‐coenzyme A (acyl‐CoA) and diacylglycerol (DAG) to catalyze the formation of triacylglycerides (TAGs). The acyl transfer reaction occurs between the activated carboxylate group of the fatty acid and the free hydroxyl group on the glycerol backbone of DAG. However, how the two substrates enter DGAT1's catalytic reaction chamber and interact with DGAT1 remains elusive. This study aims to explore the structural basis of DGAT1's substrate recognition by investigating each substrate's pathway to the reaction chamber. Using a human DGAT1 cryo‐EM structure in complex with an oleoyl‐CoA substrate, we designed two different all‐atom molecular dynamics (MD) simulation systems: DGAT1away(both acyl‐CoA and DAG away from the reaction chamber) and DGAT1bound(acyl‐CoA bound in and DAG away from the reaction chamber). Our DGAT1awaysimulations reveal that acyl‐CoA approaches the reaction chamber via interactions with positively charged residues in transmembrane helix 7. DGAT1boundsimulations show DAGs entering into the reaction chamber from the cytosol leaflet. The bound acyl‐CoA's fatty acid lines up with the headgroup of DAG, which appears to be competent to TAG formation. We then converted them into TAG and coenzyme (CoA) and used adaptive biasing force (ABF) simulations to explore the egress pathways of the products. We identify their escape routes, which are aligned with their respective entry pathways. Visualization of the substrate and product pathways and their interactions with DGAT1 is expected to guide future experimental design to better understand DGAT1 structure and function.more » « less
-
Abstract Heterologous expression of polyketide synthase (PKS) genes inEscherichia colihas enabled the production of various valuable natural and synthetic products. However, the limited availability of malonyl-CoA (M-CoA) inE. coliremains a substantial impediment to high-titer polyketide production. Here we address this limitation by disrupting the native M-CoA biosynthetic pathway and introducing an orthogonal pathway comprising a malonate transporter and M-CoA ligase, enabling efficient M-CoA biosynthesis under malonate supplementation. This approach substantially increases M-CoA levels, enhancing fatty acid and polyketide titers while reducing the promiscuous activity of PKSs toward undesired acyl-CoA substrates. Subsequent adaptive laboratory evolution of these strains provides insights into M-CoA regulation and identifies mutations that further boost M-CoA and polyketide production. This strategy improvesE. colias a host for polyketide biosynthesis and advances understanding of M-CoA metabolism in microbial systems.more » « less
An official website of the United States government

