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Biology subjects

Ramis, R.

Publications and source records attributed to Ramis, R..

3 recordsLinked to original sources

Computational Analysis of ELOVL6 Structure and Inhibition for Rational Drug Design

ELOVL6 is a key enzyme in long-chain fatty acid elongation, catalyzing the conversion of C16 fatty acids into C18 fatty acids. While its role in lipid metabolism is well established, recent studies have linked ELOVL6 to metabolic and neurodegenerative diseases, making it an attractive therapeutic target. However, the absence of a resolved crystal structure and limited mechanistic understanding of its inhibition pose significant challenges for drug discovery. In this study, we employ a multi-tiered computational approach, including structure prediction, molecular dynamics (MD) simulations, and free energy calculations, to investigate the structural basis of ELOVL6 function and inhibition. We identify the most thermodynamically favorable substrate binding pathway and characterize key conformational changes associated with ligand binding. By analyzing potential inhibitor binding pockets, we determine that known inhibitors preferentially target the active site, and we validate their binding affinities against experimental data. Additionally, by comparing ELOVL6 with homologous elongases, we pinpoint potentially key amino acid residues responsible for selectivity, providing insights that could guide structure-based drug design. Our findings establish a mechanistic framework for rational inhibitor development, offering a foundation for future efforts in optimizing ELOVL6-targeting therapeutics.

bioinformatics↗

Real-time Visualization of Trigger Factor on Translating Ribosomes

Trigger Factor (TF) is an ATP-independent chaperone that assists in co-translational protein folding by associating with ribosomes to prevent aggregation. While its interaction with ribosomes has been described, real-time visualization of TF dynamics has remained elusive. Using high-speed atomic force microscopy, we imaged full 70S ribosomes under near-physiological conditions during translation. TF exhibited dynamic transitions between extended and compact conformations, forming both stable and transient contacts with ribosomal proteins uL23 and bL17 in ribosome-nascent chain complexes. Binding to non-translating ribosomes was not observed under these conditions. Molecular dynamics simulations of TF alone and in complex with ribosomal proteins supported the experimental observations. Our findings reveal the structural flexibility of TF and its selective association with active ribosomes. Our combination of experimental and computational approaches offers new insights into how TF dynamically engages ribosomes during translation to facilitate protein folding.

molecular biology↗

Molecular dynamics simulations of the calmodulin-induced alpha-helix in the SK2 calcium-gated potassium ion channel

The family of small-conductance (SK) ion channels is composed of four members (SK1, SK2, SK3, and SK4) involved in neuron-firing regulation. The gating of these channels depends on the intracellular Ca2+ concentration, and their sensitivity to this ion is provided by calmodulin (CaM). This protein binds to a specific region in SK channels known as the calmodulin-binding domain (CaMBD), an event which is essential for their gating. While CaM-binding domains are typically disordered in the absence of CaM, the SK2 channel subtype displays a small pre-folded -helical region in its CaMBD even if CaM is not present. This small helix is known to turn into a full -helix upon CaM binding, although the molecular-level details for this conversion are not fully understood yet. In this work, we offer new insights on this physiologically relevant process by means of enhanced sampling, atomistic Hamiltonian replica exchange molecular dynamics simulations, providing a more detailed understanding of CaM binding to this target. Our results show that CaM is necessary for inducing a full -helix along the SK2 CaMBD through hydrophobic interactions with V426 and L427. However, it is also necessary that W431 does not compete for these interactions; the role of the small pre-folded -helix in the SK2 CaMBD would be to stabilize W431 so that this is the case.

biophysics↗