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Structural characterization of a protein pheromone from a cold-adapted (Antarctic) single-cell eukaryote, the ciliate Euplotes nobilii
No full textFree-living species of ciliated Protozoa control their
vegetative (mitotic) proliferation and mating (sexual) processes by diffusible, cell type-specific protein signals (pheromones). One of these molecules, designated En-2, was isolated from a species, Euplotes nobilii, living in the stably cold marine waters of Antarctica, and its complete amino acid sequence of 60 residues was determined by automated Edman degradation of the whole protein and peptides generated by trypsin digestion. The proposed sequence is : DIEDFYTSETCPYKNDSQLA20-
WDTCSGGTGNCGTVCCGQCF40SFPVSQSCAGMADSNDCPNA60. The En-2 structure appears to be characterized by an adaptive insertion of a glycine-rich motif potentially
capable to confer more flexibility to a functionally critical
region of the molecule
Determinazione della sequenza amminoacidica di En-1, un secondo feromone isolato dal ciliato antartico Euplotes nobilii.
No full text
Structural characterization of En-1, a cold-adapted protein pheromone isolated from the Antarctic ciliate Euplotes nobilii.
No full textThe second of two diffusible cell signal proteins (pheromones) purified from a wild-type strain of the Antarctic ciliate, Euplotes nobilii, has been determined by automated Edman degradation of the whole molecule and peptides generated by its chymotryptic digestion. The proposed sequence of 52 amino acids of this new pheromone, designated En-1, is: NPEDWFTPDT10CAYGDSNTAW20TTCTTPGQTC30YTCCSSCFDV40VGEQACQMSA50QC. In common with the previously determined 60-amino-acid sequence of the other pheromone, En-2, it bears eight cysteines in conserved positions (presumably linked into four conserved intrachain disulfide bonds), and physicochemical features of potential significance for cold adaptation, such as a reduced hydrophobicity, an increased solvent accessibility, and an improved local backbone flexibility. However, En-1 diverges from En-2 for having evolved a threonine cluster in the place of a glycine cluster to apparently make more flexible a region that is likely functionally important
Structural characterization of a second pheromone (En-1) isolated from the Antarctic ciliate, Euplotes nobilii. J. Eukaryotic Microbiology
No full textCold-adapted Euplotes pheromones
No full textSpecies of Euplotes rely on diffusible signal proteins (pheromones) to promote their mitotic reproduction
and mating (sexual) phenomena. Two of these pheromones have recently been structurally characterized from an Antarctic species, E. nobilii, and their amino acid sequences (of 52 and 60 residues, and eight cysteines) were found to be closely related with those of E. raikovi pheromones of temperate waters. However, they diverge in physicochemical properties, such as a reduced hydrophobicity, an increased solvent accessibility and improved backbone flexibility, which together reflect their close adaptation to cold
Structural characterization of a protein pheromone from a cold-adapted (Antarctic) single-cell eukaryote, the ciliate Euplotes nobilii
No full textStructural characterization of En-1, a cold-adapted protein pheromone isolated from the Antarctic ciliate Euplotes nobilii
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