Bacillus cereus sphingomyelinase recognizes ganglioside GM3.
Biochem Biophys Res Commun
; 431(2): 164-8, 2013 Feb 08.
Article
en En
| MEDLINE
| ID: mdl-23313504
Sphingomyelinase (SMase) from Bacillus cereus (Bc-SMase) hydrolyzes sphingomyelin (SM) to phosphocholine and ceramide in a divalent metal ion-dependent manner, and is a virulence factor for septicemia. Bc-SMase has three characteristic sites, viz., the central site (catalytic site), side-edge site (membrane binding site), and ß-hairpin region (membrane binding site). Here, we show that the ß-hairpin directly binds to gangliosides, especially NeuAcα2-3Galß1-4Glcß1-1ceramide (GM3) through a carbohydrate moiety. Neuraminidase inhibited the binding of Bc-SMase to mouse peritoneal macrophages in a dose-dependent manner. SPR analysis revealed that the binding response of Bc-SMase to liposomes containing GM3 was about 15-fold higher than that to liposomes lacking GM3. Moreover, experiments with site-directed mutants indicated that Trp-284 and Phe-285 in the ß-hairpin play an important role in the interaction with GM3. The binding of W284A and F285A mutant enzymes to mouse macrophages decreased markedly in comparison to the binding by wild-type enzymes. Therefore, we conclude that GM3 is the primary cellular receptor for Bc-SMase, and that the ß-hairpin region is the tethering region for gangliosides.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Esfingomielina Fosfodiesterasa
/
Bacillus cereus
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Gangliósido G(M3)
Límite:
Animals
Idioma:
En
Revista:
Biochem Biophys Res Commun
Año:
2013
Tipo del documento:
Article
País de afiliación:
Japón
Pais de publicación:
Estados Unidos