Destructin-1 is a collagen-degrading endopeptidase secreted byPseudogymnoascus destructans, the causative agent of white-nose syndrome

Pseudogymnoascus destructansis the causative agent of whitenose syndrome, a disease that has caused the deaths of millions of bats in North America. This psychrophilic fungus proliferates at low temperatures and targets hibernating bats, resulting in their premature arousal from stupor with catastrophic consequences. Despite the impact of white-nose syndrome, little is known about the fungus itself or how it infects its mammalian host.P. destructansis not amenable to genetic manipulation, and therefore understanding the proteins involved in infection requires alternative approaches. Here, we identify hydrolytic enzymes secreted byP. destructans, and use a novel and unbiased substrate profiling technique to define active peptidases. These experiments revealed that endopeptidases are the major proteolytic activities secreted byP. destructans, and that collagen, the major structural protein in mammals, is actively degraded by the secretome. A serine endopeptidase, hereby-named Destructin-1, was subsequently identified, and a recombinant form overexpressed and purified. Biochemical analysis of Destructin-1 showed that it mediated collagen degradation, and a potent inhibitor of peptidase activity was identified. Treatment of P. destructansconditioned media with this antagonist blocked collagen degradation and facilitated the detection of additional secreted proteolytic activities, including aminopeptidases and carboxypeptidases. These results provide molecular insights into the secretome ofP. destructans, and identify serine endopeptidases that have the clear potential to facilitate tissue invasion and pathogenesis in the mammalian host.