Biomaterial Database

Binding of yeast killer toxin to a cell wall receptor on sensitive Saccharomyces cerevisiae. 1979

H Bussey, and D Saville, and K Hutchins, and R G Palfree

35S-labeled killer toxin protein bound to cells of sensitive Saccharomyces cerevisiae S14a. Strains that were resistant to toxin through mutation in the nuclear genes kre1 kre2 bound toxin only weakly. Non-radioactive toxin competed effectively with 35S-labeled toxin for binding to S14a, but did not compete significantly in the binding to mutant kre1-1. This implied that binding to kre1-1 was nonspecific. A Scatchard analysis of the specific binding to S14a gave a linear plot, with an association constant of 2.9 x 10(6) M-1 and a receptor number of 1.1 x 10(7) per cell. Killer toxin receptors were solubilized from the cell wall by zymolyase digestion. Soluble, non-dialyzable cell wall digest from S14a competed with sensitive yeast cells for 35S-labeled toxin binding and reduced toxin-dependent killing of a sensitive strain. Wall digest from kre1-1 competed only weakly for toxin binding with sensitive cells and caused little reduction of toxin-dependent killing. Although the abundant (1.1 x 10(7) per cell) receptor appeared necessary for toxin action, as few as 2.8 x 10(4) toxin molecules were necessary to kill a sensitive cell of S14a. The kinetics killing of S14a suggested that some component was saturated with toxin at a concentration 50-fold lower than that needed to saturate the wall receptor.

UI	MeSH Term	Description	Entries
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D009183	Mycotoxins	Toxic compounds produced by FUNGI.	Fungal Toxins,Mycotoxin,Toxins, Fungal
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D011955	Receptors, Drug	Proteins that bind specific drugs with high affinity and trigger intracellular changes influencing the behavior of cells. Drug receptors are generally thought to be receptors for some endogenous substance not otherwise specified.	Drug Receptors,Drug Receptor,Receptor, Drug
D002473	Cell Wall	The outermost layer of a cell in most PLANTS; BACTERIA; FUNGI; and ALGAE. The cell wall is usually a rigid structure that lies external to the CELL MEMBRANE, and provides a protective barrier against physical or chemical agents.	Cell Walls,Wall, Cell,Walls, Cell
D004352	Drug Resistance, Microbial	The ability of microorganisms, especially bacteria, to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).	Antibiotic Resistance,Antibiotic Resistance, Microbial,Antimicrobial Resistance, Drug,Antimicrobial Drug Resistance,Antimicrobial Drug Resistances,Antimicrobial Resistances, Drug,Drug Antimicrobial Resistance,Drug Antimicrobial Resistances,Drug Resistances, Microbial,Resistance, Antibiotic,Resistance, Drug Antimicrobial,Resistances, Drug Antimicrobial
D012441	Saccharomyces cerevisiae	A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.	Baker's Yeast,Brewer's Yeast,Candida robusta,S. cerevisiae,Saccharomyces capensis,Saccharomyces italicus,Saccharomyces oviformis,Saccharomyces uvarum var. melibiosus,Yeast, Baker's,Yeast, Brewer's,Baker Yeast,S cerevisiae,Baker's Yeasts,Yeast, Baker