Gene encoding the 5. 7-kilodalton chlorosome protein of Chloroflexus aurantiacus: Regulated message levels and a predicted carboxy-terminal protein extension

Journal Article · Wed Aug 01 00:00:00 EDT 1990 · Journal of Bacteriology; (USA)

OSTI ID:6532425

Theroux, S J; Redlinger, T E; Fuller, R C; Robinson, S J ^[1]

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1. Univ. of Massachusetts, Amherst (USA)

The major light-harvesting pigment of the green filamentous bacterium Chloroflexus aurantiacus is bacteriochlorophyll (Bchl) c, localized in chlorosomes attached to the inner surface of the cytoplasmic membrane. Chlorosomes consist of four polypeptides and associated pigments and lipids. Previous studies of the inducible assembly of the photosynthetic apparatus had indicated that the major chlorosomal polypeptides are present as high-molecular-weight aggregates before the appearance of mature chlorosomes, and a mechanism for posttranslational processing of a polyprotein had been proposed. The authors have isolated the gene (csmA) encoding the 5.7-kilodalton chlorosomal polypeptide from C. aurantiacus in order to determine whether this protein is synthesized as part of a polyprotein. Analysis of the nucleotide sequence of csmA indicates that the gene is not large enough to encode more than one known chlorosome polypeptide. Transcriptional analysis indicates that csmA is transcribed as a small message whose abundance is regulated in response to oxygen, so that no csmA message is detectable in cells grown aerobically in the dark. Comparison of the sequence predicted by csmA with the peptide sequence of the Bchl c binding protein purified for chlorosomes indicates that this protein is synthesized with a carboxy-terminal extension of 27 amino acids. They discuss possible roles for this carboxy-terminal extension in the assembly of chlorosomes.

• DOE Contract Number: FG02-88ER13921
• OSTI ID: 6532425
• Journal Information: Journal of Bacteriology; (USA), Vol. 172:8; ISSN 0021-9193
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CHLOROPHYLL
GENES
PHOTOSYNTHETIC BACTERIA
MOLECULAR BIOLOGY
DNA SEQUENCING
OXYGEN
PHOTOSYNTHESIS
POST-TRANSLATION MODIFICATION
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
ELEMENTS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
NONMETALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
PROTEINS
STRUCTURAL CHEMICAL ANALYSIS
SYNTHESIS
550200* - Biochemistry