Collagen molecules are structural in nature and primarily found in eukaryotic, multicellular organisms. Recently, a collagen-like protein, TrpA, was identified and characterized in 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 identify that the TrpA protein sequence is most closely associated with non-fibril forming collagen proteins. Structural modeling and circular dichroism data suggest that the glycine insertion decreases the stability of TrpA compared to uninterrupted coll... More
Collagen molecules are structural in nature and primarily found in eukaryotic, multicellular organisms. Recently, a collagen-like protein, TrpA, was identified and characterized in 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 identify that the TrpA protein sequence is most closely associated with non-fibril forming collagen proteins. Structural modeling 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 other heterotrophic bacteria found in the same environment.
