Circular dichroism analysis of the interaction between the alpha and beta subunits in a killer toxin produced by a halotolerant yeast, Pichia farinosa.

SMK toxin is a killer toxin produced by a halotolerant yeast, Pichia farinosa. It is a heterodimer consisting of alpha (63 aa) and beta (77 aa) subunits, between which no disulfide bond exists. The two subunits interact tightly with each other below pH 5.

The novel acidophilic structure of the killer toxin from halotolerant yeast demonstrates remarkable folding similarity with a fungal killer toxin.

Background: Several strains of yeasts and fungi produce proteinous substances, termed killer toxins, which kill sensitive strains. The SMK toxin, secreted by the halotolerant yeast Pichia farinosa KK1 strain, uniquely exhibits its maximum killer activity under conditions of acidic pH and high salt concentration. The toxin is composed of two distinct subunits, alpha and beta, which tightly interact with each other under acidic conditions.

Crystallization and preliminary X-ray diffraction studies of a novel killer toxin from a halotolerant yeast Pichia farinosa.

A killer toxin from a halotolerant yeast, Pichia farinosa strain KK1, was crystallized at high- and low-salt concentrations. Crystals from the high-salt solution belonged to the tetragonal space group P4(1)2(1)2 or P4(3)2(1)2, with unit-cell dimensions of a = b = 81.10, c = 118.

Selection of starter cultures for the production of kinema, a fermented soybean food of the Himalaya.

Kinema, a traditional fermented soybean food, serves as a low-cost source of protein in the diet of the people of the Himalaya. The traditional method of kinema preparation results in a product with inconsistent quality. Forty five strains of spore-forming bacteria were isolated from nine samples of kinema collected from markets in the Darjeeling hills and Sikkim in India.