The human-specific action of intermedilysin, a homolog of streptolysin O, is dictated by domain 4 of the protein
| Autor: | Wataru Ito, Takuya Maeda, Hiroki Kourai, Ooki Ohnishi, Katsuhiko Hirota, Hideaki Nagamune, Graeme J. M. Cowan, Akiko Sukeno, Timothy J. Mitchell, Kazuto Ohkura, Kanako Hattori, Yoichiro Miyake, Miki Yamato |
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| Rok vydání: | 2004 |
| Předmět: |
Models
Molecular Immunology Mutant Molecular Sequence Data Biology Microbiology Hemolysis Cell membrane Bacterial Proteins Bacteriocins Microscopy Electron Transmission Species Specificity Virology medicine Animals Humans Point Mutation Amino Acid Sequence Binding site Peptide sequence Pore-forming toxin Binding Sites Erythrocyte Membrane Hemolysin Molecular biology medicine.anatomical_structure Cholesterol Biochemistry Liposomes Streptolysins Streptolysin Cytolysin Rabbits Streptococcus intermedius |
| Zdroj: | Microbiology and immunology. 48(9) |
| ISSN: | 0385-5600 |
| Popis: | Intermedilysin is a pore-forming cytolysin belonging to the streptolysin O gene family known as the 'Cholesterol-binding/dependent cytolysins' and is unique within the family in that it is highly humanspecific. This specificity suggests interaction with a component of human cells other than cholesterol, the proposed receptor for the other toxins of the gene family. Indeed, intermedilysin showed no significant degree of affinity to free or liposome-embedded cholesterol. Characterization of intermedilysin undecapeptide mutants revealed that this lack of affinity to cholesterol was a result of the substitutions of intermedilysin in this region. Absorption assays with erythrocyte membranes from various animals, competitive inhibition with domain 4 of intermedilysin and liposome-binding assays of streptolysin O and intermedilysin indicated that cell membrane binding is the human-specific step of intermedilysin action, that the host cell membrane-binding site is located within domain 4 in common with other members of the family and that the receptor for this toxin is not cholesterol. The species specificity of undecapeptide mutants of intermedilysin and streptolysin O and chimeric mutants between intermedilysin and streptolysin O, and intermedilysin and pneumolysin indicated that domain 4 of intermedilysin determines the human-specific action step and the cell-binding site of domain 4 lies within the 56 amino acids of the C-terminal, excluding the undecapeptide region. |
| Databáze: | OpenAIRE |
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