Developmental rearrangement of cyanobacterial nif genes: Nucleotide sequence, open reading frames, and cytochrome P-450 homology of the Anabaena sp. strain PCC 7120 nifD element

P. J. Lammers, S. McLaughlin, S. Papin, C. Trujillo-Provencio, A. J. Ryncarz

Research output: Contribution to journalArticle

16 Scopus citations


An 11-kbp DNA element of unknown function interrupts the nifD gene in vegetative cells of Anabaena sp. strain PCC 7120. In developing heterocytes the nifD element excises from the chromosome via site-specific recombination between short repeat sequences that flank the element. The nucleotide sequence of the nifH-proximal half of the element was determined to elucidate the genetic potential of the element. Four open reading frames with the same relative orientation as the nifD element-encoded xisA gene were identified in the sequenced region. Each of the open reading frames was preceded by a reasonable ribosome-binding site and had biased codon utilization preferences consistent with low levels of expression. Open reading frame 3 was highly homologous with three cytochrome P-450 ω-hydroxylase proteins and showed regional homology to functionally significant domains common to the cytochrome P-450 superfamily. The sequence encoding open reading frame 2 was the most highly conserved portion of the sequenced region based on heterologous hybridization experiments with three genera of heterocystous cyanobacteria.

Original languageEnglish (US)
Pages (from-to)6981-6990
Number of pages10
JournalJournal of bacteriology
Issue number12
StatePublished - Jan 1 1990
Externally publishedYes


ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

Cite this