title: UV irradiation and desiccation modulate the three-dimensional extracellular matrix of Nostoc commune (Cyanobacteria).
abstract: Cyanobacterium Nostoc commune can tolerate the simultaneous stresses of desiccation, UV irradiation, and oxidation. Acidic WspA, of approximately 33.6 kDa, is secreted to the three-dimensional extracellular matrix and accounts for greater than 70% of the total soluble protein. The wspA gene of N. commune strain DRH1 was cloned and found in a single genomic copy, in a monocistronic operon. Transcription of wspA and sodF (superoxide dismutase), and synthesis and secretion of WspA, were induced upon desiccation or UV-A/B irradiation of cells. Recombinant WspA binds the UV-A/B absorbing pigment scytonemin through non-covalent interactions. WspA peptide polymorphism, and heterogeneity of multiple wspA sequences within cells of a single colony, account for distinct WspA isoforms. WspA has no similarity to entries in the sequence databases and wspA, a possible xenolog, is restricted to a subset of strains in the "form species" N. commune characterized through group I intron phylogeny. We hypothesize that WspA plays a central role in the global stress response of N. commune through modulation of the structure and function of the three-dimensional extracellular matrix, particularly the transport, distribution, and/or macromolecular architecture of mycosporine and scytonemin UV-A/B absorbing pigment complexes.
authors.affiliation: Virginia Tech Center for Genomics, Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, USA.
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Wright
authors.forename: Sue C
authors.initials: SC
authors.lastname: Smith
authors.forename: Vinita
authors.initials: V
authors.lastname: Joardar
authors.forename: Siegfried
authors.initials: S
authors.lastname: Scherer
authors.forename: Jody
authors.initials: J
authors.lastname: Jervis
authors.forename: Andrew
authors.initials: A
authors.lastname: Warren
authors.forename: Richard F
authors.initials: RF
authors.lastname: Helm
authors.forename: Malcolm
authors.initials: M
authors.lastname: Potts
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002853:Chromatography, Liquid; D005109:Extracellular Matrix / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000378:metabolism; D007211:Indoles / Q000737:chemistry / Q000378:metabolism; D007525:Isoelectric Focusing; D013058:Mass Spectrometry; D008956:Models, Chemical; D008957:Models, Genetic; D008969:Molecular Sequence Data; D050501:Nostoc commune / Q000378:metabolism*; D016366:Open Reading Frames; D010100:Oxygen / Q000737:chemistry; D010397:Penicillanic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D010636:Phenols / Q000737:chemistry / Q000378:metabolism; D010802:Phylogeny; D011110:Polymorphism, Genetic; D011134:Polysaccharides / Q000737:chemistry; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D013482:Superoxide Dismutase / Q000378:metabolism; D014158:Transcription, Genetic; D014466:Ultraviolet Rays
chemical_list: D006360:Heat-Shock Proteins; D007211:Indoles; D010455:Peptides; D010636:Phenols; D011134:Polysaccharides; D011994:Recombinant Proteins; C083368:scytonemin; D010397:Penicillanic Acid; D013482:Superoxide Dismutase; C004408:aminopenicillanic acid; D010100:Oxygen