The role of the histidine-35 residue in the cytocidal action of HM-1 killer toxin.
Microbiology (Reading)
; 152(Pt 10): 2951-2958, 2006 Oct.
Article
in En
| MEDLINE
| ID: mdl-17005976
ABSTRACT
Diethylpyrocarbonate modification and site-directed mutagenesis studies of histidine-35 in HM-1 killer toxin (HM-1) have shown that a specific feature, the imidazole side chain of histidine-35, is essential for the expression of the killing activity. In subcellular localization experiments, wild-type HM-1 was in the membrane fraction of Saccharomyces cerevisiae BJ1824, but not the HM-1 analogue in which histidine-35 was replaced by alanine (H35A HM-1). Neither wild-type nor H35A HM-1 was detected in cellular fractions of HM-1-resistant yeast S. cerevisiae BJ1824 rhk1Delta URA3 and HM-1-insensitive yeast Candida albicans even after 1 h incubation. H35A HM-1 inhibited the activity of partially purified 1,3-beta-glucan synthase from S. cerevisiae A451, and its extent was almost the same as wild-type HM-1. Co-immunoprecipitation experiments showed that wild-type and H35A HM-1 directly interact with the 1,3-beta-glucan synthase complex. These results strongly suggest that histidine-35 has an important role in the cytocidal action of HM-1 that participates in the binding process to the HM-1 receptor protein on the cell membrane, but it is not essential for the interaction with, and inhibition of, 1,3-beta-glucan synthase.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Histidine
/
Mycotoxins
Language:
En
Journal:
Microbiology (Reading)
Journal subject:
MICROBIOLOGIA
Year:
2006
Document type:
Article
Affiliation country:
Japan