CLONING AND CHARACTERIZATION OF 2 PYRUVATE DECARBOXYLASE - GENES FROMPICHIA-STIPITIS CBS-6054

In Pichia stipitis, fermentative and pyruvate decarboxylase (PDC) acti vities increase with diminished oxygen rather than in response to ferm entable sugars, To better characterize PDC expression and regulation, two genes for PDC (PsPDC1 and PsPDC2) were cloned and sequenced from P . stipitis CBS 6054, Aside from Saccharomyces cerevisiae, from which t hree PDC genes have been characterized, P. stipitis is the only organi sm from which multiple genes for PDC have been identified and characte rized, PsPDC1 and PsPDC2 have diverged almost as far from one another as they have from the next most, closely related known yeast gene, PsP DC1 contains an open reading frame of 1,791 nucleotides encoding 597 a mino acids, PsPDC2 contains a reading Game of 1,710 nucleotides encodi ng 570 amino acids, An 81-nucleotide segment in the middle of the beta domain of PsPDC1 codes for a unique segment of 27 amino acids, which may play a role in allosteric regulation, The 5' regions of both P. st ipitis genes include two putative TATA elements that make them similar to the PDC genes from S. cerevisiae, Kluyveromyces marxianus, and Han seniaspora uvarum.