ISSN:
1432-1432
Keywords:
Dictyostelium discoideum
;
NADH: ubiquinone oxidoreductase
;
Complex I
;
NADH: ubiquinone oxidoreductase chain 5′
;
Mitochondrial DNA
;
Transfer RNA
;
Codon usage
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract A 3,345-bp fragment of Dictyostelium discoideum mitochondrial DNA (mtDNA) has been sequenced. This fragment contained the 80-kDa subunit of complex I (NADH:ubiquinone oxidoreductase), encoding a predicted amino acid sequence of 688 residues and a molecular mass of 79,805 daltons which is nuclear encoded in other metazoa. The C-terminus of the D. discoideum complex I gene shared a 10-bp overlap with NADH:ubiquinone oxidoreductase chain 5 (ND5), while 21 by 5′ were three tRNA genes (two isoleucine and a histidine) and a further 25 by 5′ of these genes is the partial sequence (104 residues) of an unidentified open reading frame (ORF104). Both the 80-kDa subunit and the ORF104 were hydrophilic and highly charged, suggesting they are not membrane associated, unlike most mitochondrially encoded proteins in the metazoa. Sequence analysis of the 80-kDa subunit, its adjacent ND5 gene, and ORF104 indicates the universal stop codon TGA, which codes for tryptophan in nearly all nonplant mtDNA, is either unassigned or coding for a stop codon in D. discoideum. The large size of the mitochondrial genome (54 kb), the lack of intergenic sequence, and the apparent use of the universal code suggest D. discoideum mtDNA may encode many primitive genes that are nuclear encoded in higher organisms.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00160403
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