Abstract
Peptidyl-prolyl cis-trans isomerases (PPIases) are the only class of enzymes capable of cis-trans isomerization of the prolyl peptide bond. The PPIases, comprising of different families viz., cyclophilins, FK506-binding proteins (FKBPs), parvulins and protein phosphatase 2A phosphatase activators (PTPAs), play essential roles in different cellular processes. Though PPIase gene families have been characterized in different organisms, information regarding these proteins lacks in Penicillium species, which are commercially an important fungi group. In this study, we carried out genome-wide analysis of PPIases in different Penicillium spp. and investigated their regulation by salt stress in a halotolerant strain of Penicillium oxalicum. These analyses revealed that the number of genes encoding cyclophilins, FKBPs, parvulins and PTPAs in Penicillium spp. varies between 7-11, 2-5, 1-2, and 1-2, respectively. The halotolerant P. oxalicum depicted significant enhancement in the mycelial PPIase activity in the presence of 15% NaCl, thus, highlighting the role of these enzymes in salt stress adaptation. The PPIase activity in P. oxalicum was associated with the expression of PoxCYP18, PoxCYP23, PoxCYP41, PoxFKBP12-2, and PoxFKBP52 genes. Characterization of PPIases in Penicillium spp. will provide an important database for understanding their cellular functions and might facilitate their applications in industrial processes through biotechnological interventions.
Characterization of a novel swollenin from Penicillium oxalicum in facilitating enzymatic saccharification of cellulose
