Secretory heat-shock protein of the thermotolerant yeast Hansenula polymorpha. Identification and comparative characteristics.

Thirteen investigated strains of ascomycetous yeasts able to produce secretory heat-shock proteins (sHSPs) do not response equally to a high temperature by induction of the synthesis and secretion of these proteins. In this respect the above yeasts can be divided into three groups having a positive (I), a negative (II), and an indefinite reaction (III) to the heat shock. The thermotolerant yeast Hansenula polymorpha belongs to the first group. In this yeast heat shock induces the synthesis and secretion of sHSP gp280. This new representative differs from known sHSPs in molecular mass and subunit composition. In other respects (glycosylation, mainly extracellular localization, and the character of export into the culture medium) it displays similar properties.