title: Three-dimensional structure of the actinoporin sticholysin I. Influence of long-distance effects on protein function.
abstract: Actinoporins are water-soluble proteins with the ability to form pores upon insertion into biological membranes. They constitute a family of proteins with high degree of sequence identities but different hemolytic activities, suggesting that minor conformational arrangements result in major functional changes. A good example of this situation is the sea anemone Stichodactyla helianthus which produces two very similar actinoporins, sticholysins I (StnI) and II (StnII), but of very different hemolytic efficiency. Within this idea, given that the high resolution three-dimensional structure of StnII is already known, we have now solved that one corresponding to StnI in order to analyze the influence of particular residues on the conformation and activity of these proteins. In addition, random mutagenesis has been also used to produce five less hemolytic variants of StnI. All these mutations map to functionally relevant regions because they are probably involved in conformational changes associated with pore formation, which take place after membrane binding, and involve long-distance rearrangements of the polypeptide chain of actinoporins.
authors: Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias Químicas, Universidad Complutense, 28040 Madrid, Spain.
authors: Sara
authors: S
authors: García-Linares
authors: Inés
authors: I
authors: Castrillo
authors: Marta
authors: M
authors: Bruix
authors: Margarita
authors: M
authors: Menéndez
authors: Jorge
authors: J
authors: Alegre-Cebollada
authors: Álvaro
authors: Á
authors: Martínez-del-Pozo
authors: José G
authors: JG
authors: Gavilanes
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D006461:Hemolysis / Q000187:drug effects; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D009930:Organic Chemicals / Q000737:chemistry / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D017354:Point Mutation; D052899:Pore Forming Cytotoxic Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D012615:Sea Anemones / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D012756:Sheep
chemical_list: D009930:Organic Chemicals; D010743:Phospholipids; D052899:Pore Forming Cytotoxic Proteins; C121348:stycholysin I