title: Five Fatty Aldehyde Dehydrogenase Enzymes from Marinobacter and Acinetobacter spp. and Structural Insights into the Aldehyde Binding Pocket.
abstract: Enzymes involved in lipid biosynthesis and metabolism play an important role in energy conversion and storage and in the function of structural components such as cell membranes. The fatty aldehyde dehydrogenase (FAldDH) plays a central function in the metabolism of lipid intermediates, oxidizing fatty aldehydes to the corresponding fatty acid and competing with pathways that would further reduce the fatty aldehydes to fatty alcohols or require the fatty aldehydes to produce alkanes. In this report, the genes for four putative FAldDH enzymes fromMarinobacter aquaeoleiVT8 and an additional enzyme fromAcinetobacter baylyiwere heterologously expressed inEscherichia coliand shown to display FAldDH activity. Five enzymes (Maqu_0438, Maqu_3316, Maqu_3410, Maqu_3572, and the enzyme reported under RefSeq accession no. WP_004927398) were found to act on aldehydes ranging from acetaldehyde to hexadecanal and also acted on the unsaturated long-chain palmitoleyl and oleyl aldehydes. A comparison of the specificities of these enzymes with various aldehydes is presented. Crystallization trials yielded diffraction-quality crystals of one particular FAldDH (Maqu_3316) fromM. aquaeoleiVT8. Crystals were independently treated with both the NAD+cofactor and the aldehyde substrate decanal, revealing specific details of the likely substrate binding pocket for this class of enzymes. A likely model for how catalysis by the enzyme is accomplished is also provided.IMPORTANCEThis study provides a comparison of multiple enzymes with the ability to oxidize fatty aldehydes to fatty acids and provides a likely picture of how the fatty aldehyde and NAD+are bound to the enzyme to facilitate catalysis. Based on the information obtained from this structural analysis and comparisons of specificities for the five enzymes that were characterized, correlations to the potential roles played by specific residues within the structure may be drawn.
authors.affiliation: Department of Bioproducts and Biosystems Engineering, University of Minnesota, St. Paul, Minnesota, USA.
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Bertram
authors.affiliation: Department of Bioproducts and Biosystems Engineering, University of Minnesota, St. Paul, Minnesota, USA.
authors.forename: Kalene M
authors.initials: KM
authors.lastname: Mulliner
authors.affiliation: Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Ke
authors.initials: K
authors.lastname: Shi
authors.affiliation: Biotechnology Institute, University of Minnesota, St. Paul, Minnesota, USA.
authors.forename: Mary H
authors.initials: MH
authors.lastname: Plunkett
authors.affiliation: Department of Bioproducts and Biosystems Engineering, University of Minnesota, St. Paul, Minnesota, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Nixon
authors.affiliation: Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Serratore
authors.affiliation: Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Douglas
authors.affiliation: Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Hideki
authors.initials: H
authors.lastname: Aihara
authors.affiliation: Department of Bioproducts and Biosystems Engineering, University of Minnesota, St. Paul, Minnesota, USA bbarney@umn.edu.|Biotechnology Institute, University of Minnesota, St. Paul, Minnesota, USA.
authors.forename: Brett M
authors.initials: BM
authors.lastname: Barney
mesh_terms: D000150:Acinetobacter / Q000737:chemistry / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D000445:Aldehyde Oxidoreductases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000447:Aldehydes / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D007700:Kinetics; D053520:Marinobacter / Q000737:chemistry / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment; D013379:Substrate Specificity
chemical_list: D000447:Aldehydes; D001426:Bacterial Proteins; D000445:Aldehyde Oxidoreductases; C038828:long-chain-aldehyde dehydrogenase
keywords: Maqu_3316; Marinobacter; decanal; lipid biosynthesis; wax ester