title: Two Predicted Transmembrane Domains Exclude Very Long Chain Fatty acyl-CoAs from the Active Site of Mouse Wax Synthase.
abstract: Wax esters are used as coatings or storage lipids in all kingdoms of life. They are synthesized from a fatty alcohol and an acyl-CoA by wax synthases. In order to get insights into the structure-function relationships of a wax synthase from Mus musculus, a domain swap experiment between the mouse acyl-CoA:wax alcohol acyltransferase (AWAT2) and the homologous mouse acyl-CoA:diacylglycerol O-acyltransferase 2 (DGAT2) was performed. This showed that the substrate specificity of AWAT2 is partially determined by two predicted transmembrane domains near the amino terminus of AWAT2. Upon exchange of the two domains for the respective part of DGAT2, the resulting chimeric enzyme was capable of incorporating up to 20% of very long acyl chains in the wax esters upon expression in S. cerevisiae strain H1246. The amount of very long acyl chains in wax esters synthesized by wild type AWAT2 was negligible. The effect was narrowed down to a single amino acid position within one of the predicted membrane domains, the AWAT2 N36R variant. Taken together, we provide first evidence that two predicted transmembrane domains in AWAT2 are involved in determining its acyl chain length specificity.
authors.affiliation: Department for Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University, Justus-von-Liebig-Weg 11, 37077 Goettingen, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Kawelke
authors.affiliation: Department for Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University, Justus-von-Liebig-Weg 11, 37077 Goettingen, Germany.|Department for Plant Biochemistry, Goettingen Center for Molecular Biosciences (GZMB), Georg-August-University, Justus-von-Liebig-Weg 11, 37077 Goettingen, Germany.|Department for Plant Biochemistry, International Center for Advanced Studies of Energy Conversion (ICASEC), Georg-August-University, Justus-von-Liebig-Weg 11, 37077 Goettingen, Germany.
authors.forename: Ivo
authors.initials: I
authors.lastname: Feussner
mesh_terms: D000214:Acyl Coenzyme A / Q000378:metabolism*; D000217:Acyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D020134:Catalytic Domain; D002462:Cell Membrane / Q000378:metabolism*; D017124:Conserved Sequence; D051048:Diacylglycerol O-Acyltransferase / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D013379:Substrate Specificity
chemical_list: D000214:Acyl Coenzyme A; C000608943:AWAT2 protein, mouse; D000217:Acyltransferases; C516957:DGAT2 protein, mouse; D051048:Diacylglycerol O-Acyltransferase