Proteomes - Atelocyanobacterium thalassa (isolate ALOHA)
|Proteome name||Atelocyanobacterium thalassa (isolate ALOHA) - Reference proteome|
|Taxonomy||1453429 - Atelocyanobacterium thalassa (isolate ALOHA)|
|Last modified||February 4, 2017|
|Pan proteomei||This proteome is part of the Atelocyanobacterium thalassa (isolate ALOHA) pan proteome (fasta)|
Cyanobacteria are (usually) oxygenic, phototrophic organisms. They normally encode two photosystems (PSI and PSII) releasing electrons from water and fix carbon dioxide via the Calvin-Benson-Bassham pathway. Thus they absorb large quantities of C(O)2 and produce (O)2. Some cyanobacteria are also able to fix (N)2.
Candidatus Atelocyanobacterium thalassa (formerly UCYN-A) is a globally distributed, periodically abundant (N)2-fixing marine cyanobacterium. It was recently found to lack the oxygen producing PSII complex of the photosynthetic apparatus, indicating a novel metabolism. DNA was sequenced from UCYN-A cells collected at Station ALOHA in the North Pacific subtropical gyre 100 km north of Hawaii at 15 m depth. At 1.44 Mb the genome is unusually small for a cyanobacterium and lacks a number of major metabolic pathways including enzymes for carbon fixation, the tricarboxylic acid cycle, the Calvin cycle, biosynthesis of several amino acids and de novo purine biosynthesis, but retains sufficient electron transport capacity to generate energy and reducing power from light. The metabolic potential defined by the genome indicates that UCYN-A is either an obligate endosymbiont of a cryptic symbiotic partner or that it is adapted to obtain organic nutrition from the low concentration of organic matter in the ocean, perhaps during the demise of phytoplankton blooms (adapted from PMID 20173737). Subsequent characterization has shown it is loosely associated with a unicellular Prymnesiophyte, a picoeukaryote which may be calcifying. The cyanobacterium provides fixed nitrogen, probably in return for fixed carbon (PMID 22997339).