DNA sequence and regulation of the gene (cbpA) encoding the 42-kilodalton cytoplasmic membrane carotenoprotein of the cyanobacterium Synechococcus sp. strain PCC 7942
- Univ. of Missouri-Columbia (USA)
The gene (cbpA) coding for a carotenoid-binding protein of the cyanobacterium Synechococcus sp. strain PCC 7942 (Anacystis nidulans R2) has been cloned and sequenced. A polyclonal antibody against the protein was used to identify immunoreactive clones from a {lambda}gt11 expression library of Synechococcus strain PCC 7942. The initial positive clone ({lambda}gtAN42) contained a 0.9-kilobase (kb) chromosomal fragment, which was used to detect a larger chromosomal fragment from a {lambda}EMBL3 library. The {lambda}EMBL3 recombinant, {lambda}EM109, contained an 18-kb portion of the Synechococcus strain PCC 7942 chromosome. The open reading frame of cbpA encoded 450 amino acids which give rise to a protein of 49,113 daltons. The hydrophobicity plot indicates that the protein may have a 49-residue signal sequence which is cleaved to yield a mature protein of 43,709 daltons. The protein has been localized in the cytoplasmic membrane by biochemical procedures as well as by electron microscopic immunocytochemistry. Northern (RNA) blot analysis indicates that transcription of cbpA is tightly regulated by DNA topology, light intensity, and iron concentration. Transcription is greatly induced by growth under high light intensities and repressed during growth under iron-deficient conditions. The DNA gyrase inhibitor novobiocin specifically inhibited the light-induced transcription. In Northern blots, the gene-specific probe hybridized to two size classes of RNA, with lengths of 2.0 and 6.2 kb. Since cbpA appears to be a component of the 6.2-kb transcript, it is likely part of a larger operon.
- DOE Contract Number:
- FG02-86ER13516
- OSTI ID:
- 6945890
- Journal Information:
- Journal of Bacteriology; (USA), Journal Name: Journal of Bacteriology; (USA) Vol. 171:6; ISSN JOBAA; ISSN 0021-9193
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
CAROTENOIDS
CLONING
CYANOBACTERIA
DNA
DNA HYBRIDIZATION
DNA SEQUENCING
DNA-CLONING
GENE OPERONS
GENE REGULATION
HYBRIDIZATION
HYDROCARBONS
MICROORGANISMS
MOLECULAR BIOLOGY
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PIGMENTS
PROTEINS
RECOMBINANT DNA
STRUCTURAL CHEMICAL ANALYSIS
TERPENES
TRANSCRIPTION