THE PEROXISOMAL MEMBRANE-PROTEINS OF CANDIDA-BOIDINII - GENE ISOLATION AND EXPRESSION

Candida boidinii is a methylotrophic yeast in which several growth sub strates can cause vigorous peroxisomal proliferation. While such diver se substrates as methanol, oleic acid and D-alanine induce different p eroxisomal metabolic pathways, membranes seem to contain common abunda nt peroxisomal membrane proteins (PMPs). These proteins have been term ed PMP31, PMP32 and PMP47. The gene encoding PMP47 has been previously cloned and analysed. We now report the isolation of a second PMP47 ge ne (or allele) as well as PMP31 and PMP32. PMP47A and PMP47B shark 95% sequence identity at the amino acid level. PMP31 and PMP32 each conta in 256 amino acids and are highly similar (97% identity) in protein se quence. Both PMP31 and PMP32 are predicted to span the membrane once o r twice. All abundant PMPs of C. boidinii are basic in charge; they al l have predicted isoelectric points above 10. RNAs corresponding to th e PMP47s and to PMPs31-32 are strongly induced by methanol, oleic acid and D-alanine. While the PMP47s probably encode substrate carriers, t he functions of PMP31 and PMP32 from C. boidinii are still unknown. Th e GenBank Accession Numbers for PMP47B, PMP31, and PMP32 are L27998, L 27999 and L28000, respectively. The 5' untranslated sequence of PMP47A , accession number J05672, has been corrected.