A manganese superoxide dismutase (MnSOD) from Ruditapes philippinarum: comparative structural- and expressional-analysis with copper/zinc superoxide dismutase (Cu/ZnSOD) and biochemical analysis of its antioxidant activities.
Superoxide dismutases (SODs), antioxidant metalloenzymes, represent the first line of defense in biological systems against oxidative stress caused by excessive reactive oxygen species (ROS), in particular O(2)(•-). Two distinct members of SOD family were identified from Manila clam Ruditapes philippinarum (abbreviated as RpMnSOD and RpCu/ZnSOD). The structural analysis revealed all common characteristics of SOD family in both RpSODs from primary to tertiary levels, including three MnSOD signatures and two Cu/ZnSOD signatures as well as invariant Mn(2+)- and Cu/Zn(2+)-binding sites in RpMnSOD and RpCu/ZnSOD, respectively. Putative RpMnSOD and RpCu/ZnSOD proteins were predicted to be localized in mitochondrial matrix and cytosol, respectively. They shared 65.2% and 63.9% of identity with human MnSOD and Cu/ZnSOD, respectively. Phylogentic evidences indicated the emergence of RpSODs within molluscan monophyletic clade. The analogous spatial expression profiles of RpSODs demonstrated their higher mRNA levels in hemocytes and gills. The experimental challenges with poly I:C, lipopolysaccharide and Vibrio tapetis illustrated the time-dependent dynamic expression of RpSODs in hemocytes and gills. The recombinant RpMnSOD was expressed in a prokaryotic system and its antioxidant property was studied. The rRpMnSOD exhibited its optimum activity at 20 °C, under alkaline condition (pH 9) with a specific activity of 3299 U mg(-1). These outcomes suggested that RpSODs were constitutively expressing inducible proteins that might play crucial role(s) in innate immunity of Manila clam.
Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea.
Navaneethaiyer
N
Umasuthan
S D N K
SD
Bathige
Kasthuri Saranya
KS
Revathy
Youngdeuk
Y
Lee
Ilson
I
Whang
Cheol Young
CY
Choi
Hae-Chul
HC
Park
Jehee
J
Lee
D000595:Amino Acid Sequence; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001483:Base Sequence; D049872:Bivalvia / Q000201:enzymology / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D020869:Gene Expression Profiling / Q000662:veterinary; D015971:Gene Expression Regulation, Enzymologic; D008070:Lipopolysaccharides / Q000276:immunology; D013058:Mass Spectrometry / Q000662:veterinary; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010802:Phylogeny; D011070:Poly I-C / Q000276:immunology; D016133:Polymerase Chain Reaction / Q000662:veterinary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment / Q000662:veterinary; D017385:Sequence Homology; D013482:Superoxide Dismutase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D014733:Vibrio / Q000276:immunology
D000975:Antioxidants; D018076:DNA, Complementary; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D013482:Superoxide Dismutase; D011070:Poly I-C