title: Structural characterization of a protein pheromone from a cold-adapted (Antarctic) single-cell eukaryote, the ciliate Euplotes nobilii.
abstract: Free-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: DIEDFYTSETCPYKNDSQLA(20)WDTCSGGTGNCGTVCCGQCF(40)SFPVSQSCAGMADSNDCPNA(60). 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.
authors.affiliation: Dipartimento di Biologia Molecolare Cellulare e Animale, University of Camerino, 62032 Camerino (MC), Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Alimenti
authors.forename: Claudio
authors.initials: C
authors.lastname: Ortenzi
authors.forename: Vito
authors.initials: V
authors.lastname: Carratore
authors.forename: Pierangelo
authors.initials: P
authors.lastname: Luporini
mesh_terms: D020816:Amino Acid Motifs / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D000864:Antarctic Regions; D002851:Chromatography, High Pressure Liquid; D003081:Cold Climate; D016812:Euplotes / Q000737:chemistry*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010449:Peptide Mapping; D010675:Pheromones / Q000737:chemistry* / Q000302:isolation & purification; D015800:Protozoan Proteins / Q000737:chemistry* / Q000302:isolation & purification; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid
chemical_list: D010675:Pheromones; D015800:Protozoan Proteins