Scallop lens Omega-crystallin (ALDH1A9): a novel tetrameric aldehyde dehydrogenase.
Scallop eye lens Omega-crystallin is an inactive aldehyde dehydrogenase (ALDH1A9) related to cytoplasmic ALDH1A1 and mitochondrial ALDH2 that migrates by gel filtration chromatography as a homodimer. Because mammalian ALDH1A1 and ALDH2 are homotetramers, we investigated the native molecular mass of scallop Omega-crystallin by multi-angle laser light scattering. The results indicate that the scallop Omega-crystallin is a tetrameric, not a dimeric protein. Moreover, phylogenetic tree analysis shows that scallop Omega-crystallin clusters with the mitochondrial ALDH2 and ALDH1B1 rather than the cytoplasmic ALDH1A, yet it lacks the mitochondrial N-terminal leader sequence characteristic of the mitochondrial ALDHs. The mitochondrial grouping, enzymatic inactivity, and anomalous gel filtration behavior make scallop cytoplasmic Omega-crystallin an interesting protein for structural studies of evolutionary adaptations to become an enzyme-crystallin.
Horwitz
Joseph
J
Jules Stein Eye Institute, UCLA School of Medicine, Los Angeles, CA 90095-7008, USA.
Ding
Linlin
L
Vasiliou
Vasilis
V
Cantore
Miriam
M
Piatigorsky
Joram
J
D000595:Amino Acid Sequence; D000818:Animals; D008969:Molecular Sequence Data; D049897:Pectinidae / Q000201:enzymology*; D010802:Phylogeny; D016415:Sequence Alignment; D038224:omega-Crystallins / Q000737:chemistry* / Q000145:classification / Q000235:genetics
D038224:omega-Crystallins