The structural basis of fatty acid elongation by the ELOVL elongases.

Nie L., Pascoa TC., Pike ACW., Bushell SR., Quigley A., Ruda GF., Chu A., Cole V., Speedman D., Moreira T., Shrestha L., Mukhopadhyay SMM., Burgess-Brown NA., Love JD., Brennan PE., Carpenter EP.

Very long chain fatty acids (VLCFAs) are essential building blocks for the synthesis of ceramides and sphingolipids. The first step in the fatty acid elongation cycle is catalyzed by the 3-keto acyl-coenzyme A (CoA) synthases (in mammals, ELOVL elongases). Although ELOVLs are implicated in common diseases, including insulin resistance, hepatic steatosis and Parkinson's, their underlying molecular mechanisms are unknown. Here we report the structure of the human ELOVL7 elongase, which comprises an inverted transmembrane barrel surrounding a 35-Å long tunnel containing a covalently attached product analogue. The structure reveals the substrate-binding sites in the narrow tunnel and an active site deep in the membrane. We demonstrate that chain elongation proceeds via an acyl-enzyme intermediate involving the second histidine in the canonical HxxHH motif. The unusual substrate-binding arrangement and chemistry suggest mechanisms for selective ELOVL inhibition, relevant for diseases where VLCFAs accumulate, such as X-linked adrenoleukodystrophy.

DOI

10.1038/s41594-021-00605-6

Type

Journal article

Journal

Nat Struct Mol Biol

Publication Date

06/2021

Volume

28

Pages

512 - 520

Keywords

Adrenoleukodystrophy, Animals, Binding Sites, Catalytic Domain, Cloning, Molecular, Coenzyme A, Crystallography, X-Ray, Fatty Acid Elongases, Fatty Acids, HEK293 Cells, Histidine, Humans, Imidazoles, Models, Molecular, Protein Binding, Protein Conformation, Recombinant Proteins, Sf9 Cells, Spectrometry, Mass, Electrospray Ionization, Structure-Activity Relationship, Substrate Specificity

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