Biology subjects

Nguyen, G. T. T.

Publications and source records attributed to Nguyen, G. T. T..

4 recordsLinked to original sources

bioRxiv2023

A Comparative Study of Protein Structure Prediction Tools for Challenging Targets: Snake Venom Toxins

Protein structure determination is a critical aspect of biological research, enabling us to understand protein function and potential applications. Recent advances in deep learning and artificial intelligence have led to the development of several protein structure prediction tools, such as AlphaFold2 and ColabFold. However, their performance has primarily been evaluated on well-characterised proteins, and comparisons using proteins with poor reference templates are lacking. In this study, we evaluated three modelling tools on their prediction of over 1000 snake venom toxin structures with no reference templates. Our findings show that AlphaFold2 (AF2) performed the best across all assessed parameters. We also observed that ColabFold (CF) only scored slightly worse than AF2, while being computationally less intensive. All tools struggled with regions of intrinsic disorder, such as loops and propeptide regions, and performed well in predicting the structure of functional domains. Overall, our study highlights the importance of exercising caution when working with proteins that have poor reference templates, are large, and contain flexible regions. Nonetheless, leveraging computational structure prediction tools can provide valuable insights into the modelling of protein interactions with different targets and reveal potential binding sites, active sites, and conformational changes, as well as into the design of potential molecular binders for reagent, diagnostic, or therapeutic purposes. StatementRecent advances in machine learning have led to the development of new protein structure prediction tools. However, these tools have mainly been tested on well-known proteins and their performance on proteins without known templates is unclear. This study evaluated the performance of three tools on over 1000 snake venom toxins. We found that while caution is required when studying poorly characterised proteins, these tools offer valuable opportunities to understand protein function and applications.

bioinformatics↗

bioRxiv2022

Conserved intramolecular networks in GDAP1 are closely connected to CMT-linked mutations and protein stability

Charcot-Marie-Tooth disease (CMT) is the most common inherited peripheral polyneuropathy in humans, and its subtypes are linked to mutations in dozens of different genes, including the gene coding for ganglioside-induced differentiation-associated protein 1 (GDAP1). The main GDAP1-linked CMT subtypes are the demyelinating CMT4A and the axonal CMT2K. Over a hundred different missense CMT mutations in the GDAP1 gene have been reported. However, despite implications for mitochondrial fission and fusion, cytoskeletal interactions, and response to reactive oxygen species, the etiology of GDAP1-linked CMT is poorly understood at the protein level. Based on earlier structural data, CMT-linked mutations could affect intramolecular interaction networks within the GDAP1 protein. We carried out structural and biophysical analyses on several CMT-linked GDAP1 protein variants and describe new crystal structures of the autosomal recessive R120Q and the autosomal dominant A247V and R282H GDAP1 variants. These mutations reside in the structurally central helices 3, 7, and 8. In addition, solution properties of the CMT mutants R161H, H256R, R310Q, and R310W were analysed. All disease variant proteins retain close to normal structure and solution behaviour. All mutations, apart from those affecting Arg310 outside the folded GDAP1 core domain, decreased thermal stability. In addition, a bioinformatics analysis was carried out to shed light on the conservation and evolution of GDAP1, which is an outlier member of the GST superfamily. Many CMT mutation sites are highlighted in the bioinformatics analyses focusing on sequence conservation and entropy, and the analyses support the outlier nature of GDAP1 in the GST superfamily. A central role for the 6-7 loop, within a conserved interaction network, is identified for GDAP1 protein stability. To conclude, we have expanded the structural analysis on GDAP1, strengthening the hypothesis that alterations in conserved intramolecular interactions may alter GDAP1 stability and function, eventually leading to mitochondrial dysfunction, impaired protein-protein interactions, and neuronal degeneration.

biochemistry↗

bioRxiv2022

Structural insights into Charcot-Marie-Tooth disease-linked mutations in human GDAP1

Charcot-Marie-Tooth disease (CMT) is the most common inherited peripheral polyneuropathy in humans, and its different subtypes are linked to mutations in dozens of different genes. Mutations in ganglioside-induced differentiation-associated protein 1 (GDAP1) cause two types of CMT, demyelinating CMT4A and axonal CMT2K. The GDAP1-linked CMT genotypes are mainly missense point mutations. Despite clinical profiling and in vivo studies on the mutations, the etiology of GDAP1-linked CMT is poorly understood. Here, we describe the biochemical and structural properties of the Finnish founding CMT2K mutation H123R as well as CMT2K-linked R120W, both of which are autosomal dominant mutations. The disease variant proteins retain close to normal structure and solution behaviour, but both present a large decrease in thermal stability. Using GDAP1 variant crystal structures, we identify a side chain interaction network between helices 3, 6, and 7, which is affected by CMT mutations, as well as a hinge in the long helix 6, which is linked to structural flexibility. Structural analysis of GDAP1 indicates that CMT may arise from disruption of specific intra- and intermolecular interaction networks, leading to alterations in GDAP1 structure and stability, and eventually, insufficient motor and sensory neuron function.

biochemistry↗

bioRxiv2020

Structure of the complete dimeric human GDAP1 core domain provides insights into ligand binding and clustering of disease mutations

Charcot-Marie-Tooth disease (CMT) is one of the most common inherited neurological disorders. Despite the common involvement of ganglioside-induced differentiation-associated protein 1 (GDAP1) in CMT, the protein structure and function, as well as the pathogenic mechanisms, remain unclear. We determined the crystal structure of the complete human GDAP1 core domain, which shows a novel mode of dimerization within the glutathione S-transferase (GST) family. The long GDAP1-specific insertion forms an extended helix and a flexible loop. GDAP1 is catalytically inactive towards classical GST substrates. Through metabolite screening, we identified a ligand for GDAP1, the fatty acid hexadecanedioic acid, which is relevant for mitochondrial membrane permeability and Ca2+ homeostasis. The fatty acid binds to a pocket next to a CMT-linked residue cluster, increases protein stability, and induces changes in protein conformation and oligomerization. The closest homologue of GDAP1, GDAP1L1, is monomeric in its full-length form. Our results highlight the uniqueness of GDAP1 within the GST family and point towards allosteric mechanisms in regulating GDAP1 oligomeric state and function.

biochemistry↗