ISSN:
1432-072X
Keywords:
B806-866 Light-harvesting complex genes
;
Chlorofiexus aurantiacus
;
Cytochrome c-554 gene
;
puf Operon
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The genes encoding the α-and β-polypeptide subunits of the B806-866 membrane-bound light-harvesting complex of Chloroflexus aurantiacus have been cloned and the nucleotide sequences determined. The gene puf2A, which encodes the B806-866 α-polypeptide, began 28 bases downstream of the stop codon of puf2B, which encodes the B806-866 β gene. The gene-encoding cytochrome c-554, puf2C, was found about 250 bp downstream of puf2A. puf2A encoded a 13 amino acid extension at the C-terminus of the B806-866 α-polypeptide that was not present in the mature protein. These genes, unlike those of purple nonsulfur bacteria, did not form a contiguous operon with puf1L or puf1M, the genes encoding the L and M subunits of the photochemical reaction center. The occurrence of the two latter genes and of puf2B and puf2A in two separate operons has not been observed in purple bacteria. Under photoheterotrophic growth conditions, puf2B and puf2A were encoded on an abundant mRNA that was 0.5 kb long. Two monocistronic transcripts for puf2C were observed that had different 5′-ends. One transcript encoding all three genes was also detected. Nucleotide sequences very similar to the consensus promoter sequence of the Escherichia coli RNA polymerase σ70 subunit were found seven and eight bases upstream of the 5′-end of mRNA encoding puf2B and for one of the monocistronic mRNA encoding puf2C, respectively.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00381786
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