Open AccessMolecular cloning and amino acid sequence of the precursor form of bovine adrenodoxin: evidence for a previously unidentified COOH-terminal peptide.
Author(s) -
Takashi Okamura,
Maliyakal E. John,
Mauricio X. Zuber,
Evan R. Simpson,
Michael R. Waterman
Publication year - 1985
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.82.17.5705
Subject(s) - adrenodoxin , cholesterol side chain cleavage enzyme , complementary dna , peptide sequence , biology , amino acid , biochemistry , aldosterone synthase , cdna library , microbiology and biotechnology , nucleic acid sequence , adrenal cortex , messenger rna , cytochrome , gene , enzyme , renin–angiotensin system , blood pressure , endocrinology
Several recombinant cDNA clones specific for the mitochondrial iron-sulfur protein adrenodoxin have been identified in a bovine adrenocortical cDNA library. One clone (pBAdx4) contains a 900-base-pair insert that includes the entire amino acid coding region of the adrenodoxin precursor protein. The amino acid sequence of mature adrenodoxin deduced from the nucleotide sequence of pBAdx4 is identical with that determined by protein sequencing except for three amide changes. The previously undetermined sequence of the adrenodoxin NH2-terminal precursor segment (58 amino acids) contains several basic residues, a characteristic feature of the precursor segment of proteins destined for mitochondria. In addition, a 14 amino acid extension is present at the COOH terminus of the mature adrenodoxin sequence. Whether this represents a COOH-terminal precursor segment is not clear. Three different adrenodoxin mRNAs are present [1.75, 1.4, and 0.95 kilobase(s) long] in bovine adrenocortical RNA. RNA from bovine corpus luteum, liver, and kidney contains transcripts that hybridize to adrenodoxin cDNA. Accumulation of adrenodoxin mRNA occurs in cultured bovine adrenocortical cells after treatment with ACTH or dibutyryl-cAMP, similar to that observed for the mitochondrial steroid hydroxylases that it services--namely, the cholesterol side-chain-cleavage cytochrome P-450 and the steroid 11 beta-hydroxylase cytochrome P-450.