CHARACTERIZATION OF SMALL HEAT-SHOCK PROT EINS IN LACTIC-ACID BACTERIA

Among heat shock proteins (Hsp), low molecular weight Hsp (smHsp) an t he less known. Four smHsp were recently studied in lactic acid bacteri a (Steptococcus thermophilus, Lactobacillus delbrueckii, Lactobacillus helveticus et Oenococcus oeni). These smHsp are related to Eukaryotic alpha-crystallins able to form high molecular weight complexes with a chaperoning activity. Induction factors of smHsp vary with the lactic acid bacterium. The expression of L. helveticus and O. oeni smHsp gen es are governed by different promoter structures. In L. helveticus, th e regulation system is Like Lactococcus lactis stress genes already kn own with a vegetative promoter and a CIRCE sequence. In O. oeni, the r egulation seems to be closely related to the class III stress genes, t he less known mechanism of regulation in Bacillus subtilis. (C) Inra/E lsevier, Paris.