posted on 2021-05-12, 15:03authored bySatyam Khanal, Roberto J. Brea, Michael D. Burkart, Neal K. Devaraj
The de novo formation of lipid membranes from
minimal reactive precursors is a major goal in synthetic cell research.
In nature, the synthesis of membrane phospholipids is orchestrated
by numerous enzymes, including fatty acid synthases and membrane-bound
acyltransferases. However, these enzymatic pathways are difficult
to fully reproduce in vitro. As such, the reconstitution
of phospholipid membrane synthesis from simple metabolic building
blocks remains a challenge. Here, we describe a chemoenzymatic strategy
for lipid membrane generation that utilizes a soluble bacterial fatty
acid synthase (cgFAS I) to synthesize palmitoyl-CoA in situ from acetyl-CoA and malonyl-CoA. The fatty acid derivative spontaneously
reacts with a cysteine-modified lysophospholipid by native chemical
ligation (NCL), affording a noncanonical amidophospholipid that self-assembles
into micron-sized membrane-bound vesicles. To our knowledge, this
is the first example of reconstituting phospholipid membrane formation
directly from acetyl-CoA and malonyl-CoA precursors. Our results demonstrate
that combining the specificity and efficiency of a type I fatty acid
synthase with a highly selective bioconjugation reaction provides
a biomimetic route for the de novo formation of membrane-bound
vesicles.