title: The effect of cholesterol on the long-range network of interactions established among sea anemone Sticholysin II residues at the water-membrane interface.
abstract: Actinoporins are α-pore forming proteins with therapeutic potential, produced by sea anemones. Sticholysin II (StnII) from Stichodactyla helianthus is one of its most extensively characterized members. These proteins remain stably folded in water, but upon interaction with lipid bilayers, they oligomerize to form a pore. This event is triggered by the presence of sphingomyelin (SM), but cholesterol (Chol) facilitates pore formation. Membrane attachment and pore formation require changes involving long-distance rearrangements of residues located at the protein-membrane interface. The influence of Chol on membrane recognition, oligomerization, and/or pore formation is now studied using StnII variants, which are characterized in terms of their ability to interact with model membranes in the presence or absence of Chol. The results obtained frame Chol not only as an important partner for SM for functional membrane recognition but also as a molecule which significantly reduces the structural requirements for the mentioned conformational rearrangements to occur. However, given that the DOPC:SM:Chol vesicles employed display phase coexistence and have domain boundaries, the observed effects could be also due to the presence of these different phases on the membrane. In addition, it is also shown that the Arg51 guanidinium group is strictly required for membrane recognition, independently of the presence of Chol.
authors: Department of Biochemistry and Molecular Biology I, Complutense University, 28040 Madrid, Spain. saraglinares@gmail.com.
authors: Sara
authors: S
authors: García-Linares
authors: Biochemistry, Department of Biosciences, Åbo Akademi University, 20520 Turku, Finland. iasalm@tutu.fi.
authors: Ida
authors: I
authors: Alm
authors: Biochemistry, Department of Biosciences, Åbo Akademi University, 20520 Turku, Finland. terhi.kuru@abo.fi.
authors: Terhi
authors: T
authors: Maula
authors: Department of Biochemistry and Molecular Biology I, Complutense University, 28040 Madrid, Spain. ppgf@bbm1.ucm.es.
authors: José G
authors: JG
authors: Gavilanes
authors: Biochemistry, Department of Biosciences, Åbo Akademi University, 20520 Turku, Finland. jpslotte@abo.fi.
authors: Johan Peter
authors: JP
authors: Slotte
authors: Department of Biochemistry and Molecular Biology I, Complutense University, 28040 Madrid, Spain. saraglinares@gmail.com.
authors: Álvaro
authors: Á
authors: Martínez-Del-Pozo
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001120:Arginine / Q000737:chemistry; D002784:Cholesterol / Q000737:chemistry*; D003064:Cnidarian Venoms / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000633:toxicity; D006461:Hemolysis / Q000187:drug effects; D053878:Hemolytic Agents / Q000737:chemistry* / Q000378:metabolism / Q000633:toxicity; D008051:Lipid Bilayers / Q000737:chemistry*; D021962:Membrane Microdomains / Q000737:chemistry; D008954:Models, Biological; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D010713:Phosphatidylcholines / Q000737:chemistry; D052899:Pore Forming Cytotoxic Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000633:toxicity; D016062:Porosity; D055503:Protein Multimerization; D055550:Protein Stability; D020836:Protein Structure, Quaternary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012615:Sea Anemones / Q000737:chemistry*; D034561:Sheep, Domestic; D013109:Sphingomyelins / Q000737:chemistry; D013499:Surface Properties
chemical_list: D003064:Cnidarian Venoms; D053878:Hemolytic Agents; D008051:Lipid Bilayers; D050505:Mutant Proteins; D010713:Phosphatidylcholines; D052899:Pore Forming Cytotoxic Proteins; D011994:Recombinant Proteins; D013109:Sphingomyelins; C404794:sticholysin II; D001120:Arginine; D002784:Cholesterol; C017251:1,2-oleoylphosphatidylcholine