Functional analysis of thioredoxin from the desert lichen-forming fungus, Endocarpon pusillum Hedwig, reveals its role in stress tolerance

摘要: Endocarpon pusillum is a lichen-forming fungus with an outstanding stress resistance property closely related to its antioxidant system. In this study, thioredoxin (Trx), one of the main components defense systems in E. (EpTrx), was characterized and analyzed both transgenic yeasts vitro. Our analyses identified that heterologous expression EpTrx yeast Pichia pastoris significantly enhanced osmotic oxidative stresses. Assays vitro showed acted as disulfide reductase well molecular chaperone by assembling into various polymeric structures. Upon exposure heat-shock stress, exhibited weaker activity but stronger activity, which coincided switching protein complexes from low weight forms high complexes. Specifically, we found Cys31 near not at active site crucial promoting structural functional transitions, most likely accelerating formation intermolecular bond. Transgenic Saccharomyces cerevisiae harboring native tolerance oxidative, temperature stresses than corresponding strain containing mutant (C31S). results provide first evidence on how Trx influences response fungi.