Bussey H, Sherman D, Somers J M
J Bacteriol. 1973 Mar;113(3):1193-7. doi: 10.1128/jb.113.3.1193-1197.1973.
Yeast killer factor proteins bind to cells of both sensitive and killer-producing strains, although the latter are immune to killer action. Spheroplasts prepared from sensitive cells bind less than 1% of the killer bound to whole cells, but remain fully sensitive to killer. This finding and those obtained from binding studies of partially purified, radioactive killer protein suggest that most of the toxins remain bound to the yeast cell wall and do not function further in the killing process. A killer-resistant mutant R(18) was isolated from a sensitive strain. Whole cells of the mutant were unable to bind killer and were fully resistant. In contrast, spheroplasts of R(18) were fully sensitive to killer. These data suggest that the sites exposed to killer in spheroplasts are distinct from those on the cell wall. These wall sites appear to be necessary for killer action in whole cells.
酵母杀伤因子蛋白可与敏感菌株和产杀伤因子菌株的细胞结合，尽管后者对杀伤作用具有免疫性。从敏感细胞制备的原生质体结合的杀伤因子不到与完整细胞结合的杀伤因子的1%，但仍对杀伤因子完全敏感。这一发现以及从部分纯化的放射性杀伤蛋白的结合研究中获得的结果表明，大多数毒素仍与酵母细胞壁结合，在杀伤过程中不再发挥进一步作用。从敏感菌株中分离出了一个抗杀伤因子突变体R(18)。该突变体的完整细胞无法结合杀伤因子，且具有完全抗性。相比之下，R(18)的原生质体对杀伤因子完全敏感。这些数据表明，原生质体中暴露于杀伤因子的位点与细胞壁上的位点不同。这些细胞壁位点似乎是完整细胞中杀伤作用所必需的。
