Biology subjects

Jovcevski, B.

Publications and source records attributed to Jovcevski, B..

3 recordsLinked to original sources

bioRxiv2026

Targeting the Mannitol Biosynthesis Pathway in Aspergillus fumigatus: Characterisation and Inhibition of Mannitol-2-Dehydrogenase

Infections caused by the opportunistic fungal pathogen Aspergillus fumigatus pose a serious public health system burden. The inherent limitations in existing antifungal drugs in conjunction with a rising emergence of antifungal resistance emphasizes an urgent need to identify and target alternative pathways crucial to survival and virulence. Targeting the fungal mannitol biosynthesis enzymes provides a promising avenue in the development of new antifungals due to the multifaceted roles mannitol fulfils in the fungal life cycle. However, a distinct lack of available structural information for these enzymes has hindered drug discovery efforts. We report the first crystal structure of mannitol-2-dehydrogenase from A. fumigatus in an unbound monomeric state (1.8 [A]) and bound to its co-factor NADH (2.1 [A]), via. a large, central cavity lined with positively charged residues that readily accommodates NADH. This interaction is further stabilised by a network of hydrogen bond interactions and {pi}-{pi} stacking between Phe45 and the nicotinamide ring of NADH. Furthermore, rigorous kinetic characterisation of A. fumigatus mannitol-2-dehydrogenase demonstrates the dose-dependent inhibitory activity of 1,4-benzoquinone, a cysteine-modifying small molecule inhibitor (IC50 = 1.2 {+/-} 0.2 nM). In addition, intact MS and proteomic analysis further reveal that 1,4-benzoquinone modifies up to five cysteine residues of mannitol-2-dehydrogenase and displays antifungal activity against A. fumigatus, which is enhanced in combination with a front-line antifungal voriconazole. From this work, we have established the foundations for a novel antifungal drug discovery avenue that targets the fungal mannitol biosynthesis pathway to better treat aspergillosis and related pathogenic infections.

biochemistry↗

bioRxiv2026

Structural and Catalytic Architecture of the Cysteine Synthase Cys1a

Antifungal drug resistance in Aspergillus fumigatus is a major global health concern. Due to the increasing frequency of drug-resistant strains, there is a growing need for novel antifungal drugs. Inhibition of the cysteine biosynthesis pathway in A. fumigatus represents a promising strategy for the development of antifungal adjuvants. Within this pathway, the previously uncharacterised enzyme AfuCys1a fulfils several desirable characteristics as an adjuvant target. To enable structure-based inhibitor design, AfuCys1a was structurally and functionally characterised using X-ray crystallography, biochemical assays, and comparative sequence and structural analysis. In the search for effective and viable adjuvants, this research characterises the catalytic mechanism and substrate recognition of AfuCys1a and identifies 2-picolinic acid and related compounds as promising starting points for inhibitor development, working towards the larger goal of combating rising deaths from infection by A. fumigatus.

biochemistry↗

bioRxiv2025

A ternary switch determines ERα LBD conformation

The transcription factor estrogen receptor (ER) is the primary driver of ER+ breast cancer progression and a target of multiple FDA-approved anticancer drugs. Ligand-dependent activity of ER is determined by the conformation of helix-12 (H12) within the ligand binding domain (LBD), but how H12 transitions from an unliganded (apo) state to active (estrogen-bound) or inactive (SERM/SERD-bound) states remains unresolved. Here, we present the first crystal structure of an apo ER LBD, revealing a third distinct H12 conformation that regulates receptor activity. Structural mass-spectrometry, small-angle X-ray scattering, functional analysis and molecular dynamics simulations reveal that the apo conformation of H12 is stable in the absence of ligand, but is destabilised by Y537S and D538G breast cancer mutations driving constitutive activation. We propose a model in which H12 functions as a ternary molecular switch to determine receptor activity. These findings provide critical insights into the ligand-dependent and -independent regulation of ER and have significant implications for therapeutic intervention.

biochemistry↗