title: The TrpA protein of Trichodesmium erythraeum IMS101 is a non-fibril-forming collagen and a component of the outer sheath.
abstract: Collagen molecules are structural in nature and primarily found in eukaryotic, multicellular organisms. Recently, a collagen-like protein, TrpA, was identified and characterized in the marine cyanobacterium Trichodesmium erythraeum IMS 101, and it was shown to be involved in maintaining the structural integrity of the trichomes. The TrpA protein contains one glycine interruption in the otherwise perfectly uninterrupted collagenous domain. In this study, we used phylogenetic analysis to determine that the TrpA protein sequence is most closely associated with non-fibril-forming collagen proteins. Structural modelling and circular dichroism data suggest that the glycine insertion decreases the stability of TrpA compared to uninterrupted collagen sequences. Additionally, scanning electron microscopy revealed that TrpA is expressed entirely on the surface of the trichomes, with no specific pattern of localization. These data indicate that the TrpA protein is part of the outer sheath of this organism. As such, this protein may function to promote adhesion between individual T. erythraeum trichomes, and between this organism and heterotrophic bacteria found in the same environment.
authors.affiliation: Department of Biology, Drexel University, 3245 Chestnut Street, Philadelphia, PA 19104, USA.
authors.forename: Simara
authors.initials: S
authors.lastname: Price
authors.affiliation: Department of Chemistry, Drexel University, 3245 Chestnut Street, Philadelphia, PA 19104, USA.
authors.forename: Siobhan
authors.initials: S
authors.lastname: Toal
authors.affiliation: Department of Biology, Drexel University, 3245 Chestnut Street, Philadelphia, PA 19104, USA.
authors.forename: Shivanthi
authors.initials: S
authors.lastname: Anandan
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002942:Circular Dichroism; D016000:Cluster Analysis; D003094:Collagen / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000458:Cyanobacteria / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D008958:Models, Molecular; D010802:Phylogeny; D055550:Protein Stability; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D003094:Collagen