Biology subjects

Young, P. G.

Publications and source records attributed to Young, P. G..

2 recordsLinked to original sources

bioRxiv2025

Protease mimicry: dissecting the ester bond crosslinking mechanics in bacterial adhesin proteins

The ester bond crosslink discovered within bacterial adhesin proteins offers a captivating insight into the convergent evolution of enzyme-like machinery. Crystal structures reveal a putative catalytic triad comprising an acid-base-nucleophile combination and an oxyanion-like site that suggest a serine protease-like mechanism drives the crosslinking process. We now provide confirmation of the mechanism, revealing functional catalytic dyads or triads, and the recapitulation of protease machinery from a Pseudomonas bacterium and a human cytomegalovirus related only by convergent evolution. Molecular dynamics simulations show how a conservative threonine-to-serine mutation of the nucleophile induces hydrolysis and eliminates the ester bond crosslink. Collectively, our structural, functional, and computational efforts detail the molecular intricacies of intramolecular ester bond formation and underscore the convergent evolutionary adaptations of bacteria in exploiting enzyme-like machinery to protect essential adhesin proteins from the mechanical, biological, and chemical hostilities of the bacterias replicative niche.

biochemistry↗

bioRxiv2025

Molecular mechanisms of plastic biodegradation by the fungus Clonostachys rosea

Microbial degradation provides an avenue for the remediation of select plastic polymers contributing to the urgent environmental problem of global plastic pollution. We demonstrate the degradation of polycaprolactone (PCL) by Clonostachys rosea and elucidate its underlying molecular mechanisms. We constructed the genome of this fungal strain and monitored changes in gene expression when exposed to PCL. Twelve genes linked to PCL degradation were found in the genome of C. rosea, and some of them were upregulated in the presence of the plastic, including genes coding for two cutinases. We heterologously expressed the enzymes coded by both genes and confirmed their activity against PCL polymers. We also demonstrate that one of the enzymes was active against polyethylene terephthalate (PET) polymers. Glucose inhibited the expression of both genes, completely halting the plastic biodegradation process, possibly serving as a preferred and readily metabolisable carbon source compared with PCL. We confirm the presence of key metabolic pathways linked to PCL degradation in C. rosea, including fatty acid degradation, providing further evidence of the mechanisms central to plastic biodegradation.

microbiology↗