Resolving coupled pH titrations using alchemical free energy calculations.

In a protein, nearby titratable sites can be coupled: the (de)protonation of one may affect the other. The degree of this interaction depends on several factors and can influence the measured . Here, we derive a formalism based on double free energy differences ( ) for quantifying the individual site values of coupled residues.

Molecular basis for human aquaporin inhibition.

Cancer invasion and metastasis are known to be potentiated by the expression of aquaporins (AQPs). Likewise, the expression levels of AQPs have been shown to be prognostic for survival in patients and have a role in tumor growth, edema, angiogenesis, and tumor cell migration. Thus, AQPs are key players in cancer biology and potential targets for drug development.

Accurately Predicting Protein p Values Using Nonequilibrium Alchemy.

The stability, solubility, and function of a protein depend on both its net charge and the protonation states of its individual residues. p is a measure of the tendency for a given residue to (de)protonate at a specific pH. Although p values can be resolved experimentally, theory and computation provide a compelling alternative.

AlphaFold2: A Role for Disordered Protein/Region Prediction?

The development of AlphaFold2 marked a paradigm-shift in the structural biology community. Herein, we assess the ability of AlphaFold2 to predict disordered regions against traditional sequence-based disorder predictors. We find that AlphaFold2 performs well at discriminating disordered regions, but also note that the disorder predictor one constructs from an AlphaFold2 structure determines accuracy.

Matrin3: Disorder and ALS Pathogenesis.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the degeneration of both upper and lower motor neurons in the brain and spinal cord. ALS is associated with protein misfolding and inclusion formation involving RNA-binding proteins, including TAR DNA-binding protein (TDP-43) and fused in sarcoma (FUS). The 125-kDa Matrin3 is a highly conserved nuclear DNA/RNA-binding protein that is implicated in many cellular processes, including binding and stabilizing mRNA, regulating mRNA nuclear export, modulating alternative splicing, and managing chromosomal distribution.

KEAP1 Cancer Mutants: A Large-Scale Molecular Dynamics Study of Protein Stability.

We have performed 280 μs of unbiased molecular dynamics (MD) simulations to investigate the effects of 12 different cancer mutations on Kelch-like ECH-associated protein 1 (KEAP1) (G333C, G350S, G364C, G379D, R413L, R415G, A427V, G430C, R470C, R470H, R470S and G476R), one of the frequently mutated proteins in lung cancer. The aim was to provide structural insight into the effects of these mutants, including a new class of ANCHOR (additionally NRF2-complexed hypomorph) mutant variants. Our work provides additional insight into the structural dynamics of mutants that could not be analyzed experimentally, painting a more complete picture of their mutagenic effects.

Exploring the Conformational Landscape of the Neh4 and Neh5 Domains of Nrf2 Using Two Different Force Fields and Circular Dichroism.

The nuclear factor erythroid 2-related factor 2 (Nrf2)-ARE transcriptional response pathway plays a critical role in protecting the cell from oxidative stresses via the upregulation of cytoprotective genes. Aberrant activation of Nrf2 in cancer cells can confer this cytoprotectivity, thereby reducing the efficacy of both chemotherapeutics and radiotherapies. Key to this antioxidant pathway is the interaction between Nrf2 and CREB binding protein (CBP), mediated by the Neh4 and Neh5 domains of Nrf2.