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B6db references: .23957439

type Journal Article
authors Wadsworth JM1, Clarke DJ, McMahon SA, Lowther JP, Beattie AE, Langridge-Smith PR, Broughton HB, Dunn TM, Naismith JH, Campopiano DJ.
title The chemical basis of serine palmitoyltransferase inhibition by myriocin.
journal J Am Chem Soc.
sel unselected
ui 23957439
year (2013)
volume 135
number 38
pages 14276-85
abstract Sphingolipids (SLs) are essential components of cellular membranes formed from the condensation of L-serine and a long-chain acyl thioester. This first step is catalyzed by the pyridoxal-5'-phosphate (PLP)-dependent enzyme serine palmitoyltransferase (SPT) which is a promising therapeutic target. The fungal natural product myriocin is a potent inhibitor of SPT and is widely used to block SL biosynthesis despite a lack of a detailed understanding of its molecular mechanism. By combining spectroscopy, mass spectrometry, X-ray crystallography, and kinetics, we have characterized the molecular details of SPT inhibition by myriocin. Myriocin initially forms an external aldimine with PLP at the active site, and a structure of the resulting co-complex explains its nanomolar affinity for the enzyme. This co-complex then catalytically degrades via an unexpected 'retro-aldol-like' cleavage mechanism to a C18 aldehyde which in turn acts as a suicide inhibitor of SPT by covalent modification of the essential catalytic lysine. This surprising dual mechanism of inhibition rationalizes the extraordinary potency and longevity of myriocin inhibition.
last changed 2014/03/20 11:23

B6db references