Microarray analysis of S. cerevisiae submitted to Hydrostatic Pressure (HP) revealed that this stress causes gene expression modifications, leading to a stress response profile. However, unknown genes were among the 10 highest expressed representing 45% of the induced total. Therefore, we selected 9 of those genes for further functional and structural analysis. The up-regulation of YER067W, YFL014W, YDR070C, YLR327C, YMR107W, YDL110C, YPR096C, YNL266W, YNL198C was confirmed by semi-quantitative RT-PCR in 2 situations: 200 and 50MPa for 30 min. To recognize the folding of these putative proteins and then, gain insights about the function and mechanisms involved in cell survival against HP, the cDNAs were inserted in pET28a plasmid and heterologous expressed in E. coli. Sequences were fusioned to a N-terminal hexahistine tag followed by a thrombin cleavage site. We carried out the expression of Ydr070cp, Yer067wp, Ymr107wp and Yfl014wp. After 4 hours of IPTG induction, the soluble fraction presented a clear protein band with the expected molecular weight for all 4 putative proteins yielding 2,5; 2,9; 4,7 and 3,6 mg of purified protein/100 ml. In the purification step proteins bound to Ni²⁺ affinity resin were eluted with 300 mM imidazol. Circular dichroism of Yfl014wp (Hsp12p) and Ydr070cp revealed a predominance of a random structure. However the presence of 0,1% SDS promoted a gain of structure for both proteins suggesting that, this protein may be interacting with cellular membranes. Further results involving NMR and fluorescence spectroscopy will unveil structural features for those unknown proteins. Supported by CNPq, FAPERJ