6D6Y

AprA Methyltransferase 2 - GNAT didomain in complex with SAH

Summary for 6D6Y

• Entry DOI: 10.2210/pdb6d6y/pdb
• Descriptor: AprA Methyltransferase 2, trimethylamine oxide, S-ADENOSYL-L-HOMOCYSTEINE, ... (4 entities in total)
• Functional Keywords: methyltransferase, decarboxylase, apratoxin, gcn5 related n-acetyltransferase, transferase
• Biological source: Moorea bouillonii
• Total number of polymer chains: 1
• Total formula weight: 60590.46

Authors

Sikkema, A.P.,Smith, J.L. (deposition date: 2018-04-23, release date: 2018-05-09, Last modification date: 2024-10-30)

Primary citation

Skiba, M.A.,Sikkema, A.P.,Moss, N.A.,Lowell, A.N.,Su, M.,Sturgis, R.M.,Gerwick, L.,Gerwick, W.H.,Sherman, D.H.,Smith, J.L.
Biosynthesis of t-Butyl in Apratoxin A: Functional Analysis and Architecture of a PKS Loading Module.
ACS Chem. Biol., 13:1640-1650, 2018

PubMed Abstract: The unusual feature of a t-butyl group is found in several marine-derived natural products including apratoxin A, a Sec61 inhibitor produced by the cyanobacterium Moorea bouillonii PNG 5-198. Here, we determine that the apratoxin A t-butyl group is formed as a pivaloyl acyl carrier protein (ACP) by AprA, the polyketide synthase (PKS) loading module of the apratoxin A biosynthetic pathway. AprA contains an inactive "pseudo" GCN5-related N-acetyltransferase domain (ΨGNAT) flanked by two methyltransferase domains (MT1 and MT2) that differ distinctly in sequence. Structural, biochemical, and precursor incorporation studies reveal that MT2 catalyzes unusually coupled decarboxylation and methylation reactions to transform dimethylmalonyl-ACP, the product of MT1, to pivaloyl-ACP. Further, pivaloyl-ACP synthesis is primed by the fatty acid synthase malonyl acyltransferase (FabD), which compensates for the ΨGNAT and provides the initial acyl-transfer step to form AprA malonyl-ACP. Additionally, images of AprA from negative stain electron microscopy reveal multiple conformations that may facilitate the individual catalytic steps of the multienzyme module.

PubMed: 29701944
DOI: 10.1021/acschembio.8b00252

Experimental method

X-RAY DIFFRACTION (2.246 Å)