Siloto RMP, Madhavji M, Wiehler WB, Burton TL, Boora PS, Laroche A, Weselake RJ. An N-terminal fragment of mouse DGAT1 binds different acyl-CoAs with varying affinity.
Biochem Biophys Res Commun 2008;
373:350-4. [PMID:
18571500 DOI:
10.1016/j.bbrc.2008.06.031]
[Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Accepted: 06/05/2008] [Indexed: 10/21/2022]
Abstract
A histidine-tagged recombinant N-terminal fragment of type-1 mouse liver diacylglycerol acyltransferase (DGAT; EC 2.3.1.20), MmDGAT1(1-95)His6, was expressed in Escherichia coli, and used to investigate possible acyl-CoA-binding properties. Analysis of the purified fragment by MALDI-TOF mass spectrometry revealed a polypeptide with molecular mass of about 11 kDa which was consistent with the calculated molecular mass based on the deduced amino acid sequence. Lipidex-1000 binding assays indicated that MmDGAT1(1-95)His(6) interacted with long chain fatty acyl-CoAs similar to observations on DGAT1 from oilseed rape (Brassica napus). Binding, as a function of acyl-CoA concentration, differed for palmitoyl (16:0), stearoyl (18:0), and erucoyl (cisDelta(13)22:1)-CoA. Binding of stearoyl- or erucoyl-CoA to MmDGAT1(1-95)His(6) as a function of acyl-CoA concentration, however, was sigmoid and displayed positive cooperativity suggesting that MmDGAT1 may be subject to allosteric modulation by acyl-CoAs. An intra-polypeptide segment within the N-terminal region of MmDGAT1 contained remnants of an acyl-CoA-binding signature initially identified in plant DGAT1. The acyl-CoA-binding site in mammalian DGAT1 could represent a potential target for therapeutic interventions for disorders such as type-2 diabetes and obesity.
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