RT Journal Article SR Electronic(1) A1 Miyamoto, Masahiko A1 Onozato, Naohiko A1 Selvakumar, Dakshnamurthy A1 Kimura, Tetsuya A1 Furuichi, Yasuhiro A1 Komiyama, TadazumiYR 2006 T1 The role of the histidine-35 residue in the cytocidal action of HM-1 killer toxin JF Microbiology, VO 152 IS 10 SP 2951 OP 2958 DO https://doi.org/10.1099/mic.0.29100-0 PB Microbiology Society, SN 1465-2080, AB 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 rhk1Δ : : URA3 and HM-1-insensitive yeast Candida albicans even after 1 h incubation. H35A HM-1 inhibited the activity of partially purified 1,3-β-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-β-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-β-glucan synthase., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.29100-0