Biology subjects

Moeller, N. H.

Publications and source records attributed to Moeller, N. H..

3 recordsLinked to original sources

bioRxiv2024

The structural basis for the selective antagonism of soluble TNF-alpha by shark variable new antigen receptors

The pro-inflammatory cytokine tumor necrosis factor-alpha (TNF)- is synthesized as transmembrane TNF- (tmTNF-) where proteolytic processing releases soluble TNF- (sTNF-). tmTNF- can act as either a ligand by activating TNF receptors, or a receptor that transmits outside-to-inside signals (reverse signalling) after binding to native receptors. All TNF- therapies bind tmTNF- and induce reverse signalling which can result in immunosuppression leading to infection. We present crystal structures of two anti-TNF- Variable New Antigen Receptors (VNAR) in complex with sTNF- via two distinct epitopes. The VNAR-D1 recognized an epitope that selectively engaged sTNF- while VNAR-C4 bound an epitope that overlapped with other biologic therapies. In activated CD4+ T cells, our VNARs did not bind tmTNF- in contrast to commercially available therapies that demonstrated induction of reverse signalling. Our findings suggest that neutralisation through a unique mechanism may lead to anti-TNF- agents with an improved safety profile that will benefit high-risk patients.

pharmacology and toxicology↗

bioRxiv2024

A real-time biochemical assay for quantitative analyses of APOBEC-catalyzed DNA deamination

Over the past decade, the connection between APOBEC3 cytosine deaminases and cancer mutagenesis has become increasingly apparent. This growing awareness has created a need for biochemical tools that can be used to identify and characterize potential inhibitors of this enzyme family. In response to this challenge, we have developed a Real-time APOBEC3-mediated DNA Deamination (RADD) assay. This assay offers a single-step set-up and real-time fluorescent read-out, and it is capable of providing insights into enzyme kinetics and also offering a high-sensitivity and easily scalable method for identifying APOBEC3 inhibitors. This assay serves as a crucial addition to the existing APOBEC3 biochemical and cellular toolkit and possesses the versatility to be readily adapted into a high-throughput format for inhibitor discovery.

biochemistry↗

bioRxiv2021

Structure and dynamics of SARS-CoV-2 proofreading exoribonuclease ExoN

High-fidelity replication of the large RNA genome of coronaviruses (CoVs) is mediated by a 3'-to-5' exoribonuclease (ExoN) in non-structural protein 14 (nsp14), which excises nucleotides including antiviral drugs mis-incorporated by the low-fidelity viral RNA-dependent RNA polymerase (RdRp) and has also been implicated in viral RNA recombination and resistance to innate immunity. Here we determined a 1.6-[A] resolution crystal structure of SARS-CoV-2 ExoN in complex with its essential co-factor, nsp10. The structure shows a highly basic and concave surface flanking the active site, comprising several Lys residues of nsp14 and the N-terminal amino group of nsp10. Modeling suggests that this basic patch binds to the template strand of double-stranded RNA substrates to position the 3' end of the nascent strand in the ExoN active site, which is corroborated by mutational and computational analyses. Molecular dynamics simulations further show remarkable flexibility of multi-domain nsp14 and suggest that nsp10 stabilizes ExoN for substrate RNA-binding to support its exoribonuclease activity. Our high-resolution structure of the SARS-CoV-2 ExoN-nsp10 complex serves as a platform for future development of anti-coronaviral drugs or strategies to attenuate the viral virulence.

biochemistry↗