title: The alpha glycerophosphate cycle in Drosophila melanogaster VI. structure and evolution of enzyme paralogs in the genus Drosophila.
abstract: The genome sequences of 12 Drosophila species contain 3 paralogs for alpha glycerophosphate dehydrogenase (GPDH) and for the mitochondrial alpha glycerophosphate oxidase (GPO). These 2 enzymes participate in the alpha glycerophosphate cycle in the adult thoracic flight muscles. The flight muscle enzymes are encoded by gpdh-1 at 26A2 and gpo-1 at 52C8. In this paper, we show that the GPDH paralogs share the same evolutionarily conserved functional domains and most intron positions, whereas the GPO paralogs share only some of the functional domains of mitochondrial oxidoreductases. The GPO paralogs not expressed in the flight muscles essentially lack introns. GPDH paralogs encoded by gpdh-2 and gpdh-3 and the GPO paralogs encoded by gpo-2 and gpo-3 are expressed only in the testes. Gene trees for the GPDH and GPO paralogs indicate that the genes expressed in the flight muscles are evolving very slowly presumably under strong purifying selection whereas the paralogs expressed in the testes are evolving more rapidly. The concordance between species and gene trees, d(N)/d(S) ratios, phylogenetic analysis by maximum likelihood-based tests, and analyses of radical and conservative substitutions all indicate that the additional GPDH and GPO paralogs are also evolving under purifying selection.
authors.affiliation: Department of Molecular Biology and Genetics, 407 Biotechnology Building, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Amber
authors.initials: A
authors.lastname: Carmon
authors.forename: Ross
authors.initials: R
authors.lastname: MacIntyre
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004330:Drosophila / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D005426:Flight, Animal / Q000502:physiology; D005993:Glycerolphosphate Dehydrogenase / Q000737:chemistry* / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D005994:Glycerophosphates / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism; D010802:Phylogeny; D017434:Protein Structure, Tertiary / Q000235:genetics; D017385:Sequence Homology; D013329:Structure-Activity Relationship; D013737:Testis / Q000201:enzymology / Q000378:metabolism
chemical_list: D005994:Glycerophosphates; C029620:alpha-glycerophosphoric acid; D005993:Glycerolphosphate Dehydrogenase