Primary structure of a precursor for the delta-subunit of sweet potato mitochondrial F1-ATPase deduced from full length cDNA.
A cDNA library constructed from poly(A)-rich RNA of the sweet potato tuberous root using a newly developed plasmid vector carrying tac-SP6 promoters was used to identify full length cDNAs for the nuclear-encoded delta-subunit of mitochondrial F1-ATPase by oligonucleotide-hybridization selection. Selected clones contained cDNA insert which carry the entire coding capacity for the pre-delta-subunit, since the RNA transcribed in vitro from SP6 promoter on the vector directed the synthesis of pre-delta-subunit polypeptide in a wheat germ in vitro translation assay. The nucleotide sequence of one of these cDNAs indicates that it can code for the pre-delta-subunit of 244 amino acids of which 199 amino acids encode the mature subunit. The amino acid sequence of the mature delta-subunit shows similarities of about 18-25% amino acid positional identity with the delta-subunits of bacterial F1-ATPases, about 26% with the delta-subunit of chloroplast CF1-ATPase, and about 32-37% with oligomycin sensitivity conferring proteins of animal and fungal mitochondria. The N-terminal presequence of the precursor composed of maximum of 45 amino acids does not show any obvious sequence homology with either the transit peptide of the nuclear-encoded pre-delta-subunit of chloroplast CF1 or the presequence of the nuclear-encoded pre-oligomycin sensitivity conferring proteins. At least two types of the delta-subunit cDNAs with very similar structures were identified from the library, and the presence of multiple copies of the delta-subunit gene in the hexaploid genome of the sweet potato is also suggested by genomic Southern blot hybridization.
Laboratory of Biochemistry, School of Agriculture, Nagoya University, Japan.
T
T
Kimura
S
S
Takeda
T
T
Asahi
K
K
Nakamura
D000595:Amino Acid Sequence; D001483:Base Sequence; D004247:DNA / Q000235:genetics*; D015723:Gene Library; D005822:Genetic Vectors; D046911:Macromolecular Substances; D008928:Mitochondria / Q000201:enzymology*; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D010944:Plants / Q000201:enzymology* / Q000235:genetics; D011061:Poly A / Q000235:genetics / Q000302:isolation & purification; D014176:Protein Biosynthesis; D006180:Proton-Translocating ATPases / Q000235:genetics*; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic
D046911:Macromolecular Substances; D015345:Oligonucleotide Probes; D012333:RNA, Messenger; D011061:Poly A; D012313:RNA; D004247:DNA; D006180:Proton-Translocating ATPases