3-ketoacyl-CoA synthase 6-Glossy2 enzyme complex (CER6-GL2)

The CER6-GL2 enzyme complex is a critical heteromeric assembly in plants, primarily responsible for the biosynthesis of very-long-chain fatty acids (VLCFAs) with chain lengths exceeding 28 carbons. It consists of the core catalytic subunit 3-ketoacyl-CoA synthase 6 (CER6 or KCS6) and a non-catalytic BAHD family protein known as Glossy2 (GL2) in maize or CER2 in Arabidopsis. While CER6 possesses the enzymatic machinery—a Cys-His-Asn catalytic triad—it is unable to produce fatty acids longer than C28 on its own. The GL2 subunit binds to CER6 to structurally remodel and expand the enzyme's substrate-binding tunnel into a continuous hydrophobic channel, enabling the elongation of acyl chains up to C34. This complex serves as a vital target in agricultural biotechnology for the development of stress-resilient crops. By modulating the activity of the CER6-GL2 complex, researchers can alter the deposition and composition of plant cuticular wax, which acts as the primary barrier against non-stomatal water loss and pathogen invasion. Recent structural studies using cryo-electron microscopy have elucidated the heterotetrameric stoichiometry of the complex, providing a molecular blueprint for engineering plants with enhanced drought tolerance and environmental adaptability. While not a target for human therapeutics, it remains a focal point for the development of novel agrochemicals and genetic traits intended to secure global food supplies under changing climatic conditions.

Other names

KCS6-GL2 complexCER6-CER2 complexβ-ketoacyl-CoA synthase 6-Glossy2ECERIFERUM6-GLABRA2KCS6-CER2-like complex

The complex catalyzes the condensation of malonyl-CoA with acyl-CoA to elongate fatty acid chains; specifically, GL2/CER2 acts as a non-catalytic subunit that remodels the substrate tunnel of CER6 to facilitate elongation beyond C28 to C34.