Publications

• Detailed characterization of the substrate specificity of mouse wax synthase.

  Miklaszewska M., Kawinski A., Banas A.

  Wax synthases are membrane-associated enzymes catalysing the esterification reaction between fatty acyl-CoA and a long chain fatty alcohol. In living organisms, wax esters function as storage materials or provide protection against harmful environmental influences. In industry, they are used as in ... >> More

  Wax synthases are membrane-associated enzymes catalysing the esterification reaction between fatty acyl-CoA and a long chain fatty alcohol. In living organisms, wax esters function as storage materials or provide protection against harmful environmental influences. In industry, they are used as ingredients for the production of lubricants, pharmaceuticals, and cosmetics. Currently the biological sources of wax esters are limited to jojoba oil. In order to establish a large-scale production of desired wax esters in transgenic high-yielding oilseed plants, enzymes involved in wax esters synthesis from different biological resources should be characterized in detail taking into consideration their substrate specificity. Therefore, this study aims at determining the substrate specificity of one of such enzymes --the mouse wax synthase. The gene encoding this enzyme was expressed heterologously in Saccharomyces cerevisiae. In the in vitro assays (using microsomal fraction from transgenic yeast), we evaluated the preferences of mouse wax synthase towards a set of combinations of 11 acyl-CoAs with 17 fatty alcohols. The highest activity was observed for 14:0-CoA, 12:0-CoA, and 16:0-CoA in combination with medium chain alcohols (up to 5.2, 3.4, and 3.3 nmol wax esters/min/mg microsomal protein, respectively). Unsaturated alcohols longer than 18°C were better utilized by the enzyme in comparison to the saturated ones. Combinations of all tested alcohols with 20:0-CoA, 22:1-CoA, or Ric-CoA were poorly utilized by the enzyme, and conjugated acyl-CoAs were not utilized at all. Apart from the wax synthase activity, mouse wax synthase also exhibited a very low acyl-CoA:diacylglycerol acyltransferase activity. However, it displayed neither acyl-CoA:monoacylglycerol acyltransferase, nor acyl-CoA:sterol acyltransferase activity. << Less

  Acta Biochim Pol 60:209-215(2013) [PubMed] [EuropePMC]

• Allosteric modulation of the substrate specificity of acyl-CoA wax alcohol acyltransferase 2.

  Arne J.M., Widjaja-Adhi M.A., Hughes T., Huynh K.W., Silvaroli J.A., Chelstowska S., Moiseenkova-Bell V.Y., Golczak M.

  The esterification of alcohols with fatty acids is a universal mechanism to form inert storage forms of sterols, di- and triacylglycerols, and retinoids. In ocular tissues, formation of retinyl esters is an essential step in the enzymatic regeneration of the visual chromophore (11-<i>cis</i>-retin ... >> More

  The esterification of alcohols with fatty acids is a universal mechanism to form inert storage forms of sterols, di- and triacylglycerols, and retinoids. In ocular tissues, formation of retinyl esters is an essential step in the enzymatic regeneration of the visual chromophore (11-<i>cis</i>-retinal). Acyl-CoA wax alcohol acyltransferase 2 (AWAT2), also known as multifunctional <i>O</i>-acyltransferase (MFAT), is an integral membrane enzyme with a broad substrate specificity that has been shown to preferentially esterify 11-<i>cis</i>-retinol and thus contribute to formation of a readily available pool of <i>cis</i> retinoids in the eye. However, the mechanism by which this promiscuous enzyme can gain substrate specificity is unknown. Here, we provide evidence for an allosteric modulation of the enzymatic activity by 11-<i>cis</i> retinoids. This regulation is independent from cellular retinaldehyde-binding protein (CRALBP), the major <i>cis</i>-retinoid binding protein. This positive-feedback regulation leads to decreased esterification rates for 9-<i>cis</i>, 13-<i>cis</i>, or all-<i>trans</i> retinols and thus enables preferential synthesis of 11-<i>cis</i>-retinyl esters. Finally, electron microscopy analyses of the purified enzyme indicate that this allosteric effect does not result from formation of functional oligomers. Altogether, these data provide the experimental basis for understanding regulation of AWAT2 substrate specificity. << Less

  J. Lipid Res. 58:719-730(2017) [PubMed] [EuropePMC]

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