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Methods in Molecular Biology (Clifton,... 2021The complex enzyme kinetics displayed by drug-metabolizing cytochrome P450 enzymes (CYPs) (see Chapter 9 ) can, in part, be explained by an examination of their...
The complex enzyme kinetics displayed by drug-metabolizing cytochrome P450 enzymes (CYPs) (see Chapter 9 ) can, in part, be explained by an examination of their crystallographic protein structures. Fortunately, despite low sequence similarity between different families of drug-metabolizing CYPs, there exists a high degree of structural homology within the superfamily. This similarity in the protein fold allows for a direct comparison of the structural features of CYPs that contribute toward differences in substrate binding, heterotropic and homotropic cooperativity, and genetic variability in drug metabolism. In this chapter, we first provide an overview of the nomenclature and the role of structural features that are common in all CYPs. We then apply these definitions to understand the different substrate specificities and functions in the CYP3A, CYP2C, and CYP2D families of enzymes.
Topics: Crystallography, X-Ray; Cytochrome P-450 Enzyme System; Genetic Variation; Humans; Inactivation, Metabolic; Kinetics; Models, Molecular; Protein Folding; Protein Structure, Secondary; Substrate Specificity
PubMed: 34272695
DOI: 10.1007/978-1-0716-1554-6_7 -
EMBO Reports Jul 2021In eukaryotic cells, DNA is tightly packed with the help of histone proteins into chromatin. Chromatin architecture can be modified by various post-translational... (Review)
Review
In eukaryotic cells, DNA is tightly packed with the help of histone proteins into chromatin. Chromatin architecture can be modified by various post-translational modifications of histone proteins. For almost 60 years now, studies on histone lysine acetylation have unraveled the contribution of this acylation to an open chromatin state with increased DNA accessibility, permissive for gene expression. Additional complexity emerged from the discovery of other types of histone lysine acylations. The acyl group donors are products of cellular metabolism, and distinct histone acylations can link the metabolic state of a cell with chromatin architecture and contribute to cellular adaptation through changes in gene expression. Currently, various technical challenges limit our full understanding of the actual impact of most histone acylations on chromatin dynamics and of their biological relevance. In this review, we summarize the state of the art and provide an overview of approaches to overcome these challenges. We further discuss the concept of subnuclear metabolic niches that could regulate local CoA availability and thus couple cellular metabolisms with the epigenome.
Topics: Acetylation; Acylation; Chromatin; Histones; Protein Processing, Post-Translational
PubMed: 34159701
DOI: 10.15252/embr.202152774 -
The Biochemical Journal Jul 2020DNA-damage tolerance (DDT) is employed by eukaryotic cells to bypass replication-blocking lesions induced by DNA-damaging agents. In budding yeast Saccharomyces... (Review)
Review
DNA-damage tolerance (DDT) is employed by eukaryotic cells to bypass replication-blocking lesions induced by DNA-damaging agents. In budding yeast Saccharomyces cerevisiae, DDT is mediated by RAD6 epistatic group genes and the central event for DDT is sequential ubiquitination of proliferating cell nuclear antigen (PCNA), a DNA clamp required for replication and DNA repair. DDT consists of two parallel pathways: error-prone DDT is mediated by PCNA monoubiquitination, which recruits translesion synthesis DNA polymerases to bypass lesions with decreased fidelity; and error-free DDT is mediated by K63-linked polyubiquitination of PCNA at the same residue of monoubiquitination, which facilitates homologous recombination-mediated template switch. Interestingly, the same PCNA residue is also subjected to sumoylation, which leads to inhibition of unwanted recombination at replication forks. All three types of PCNA posttranslational modifications require dedicated conjugating and ligation enzymes, and these enzymes are highly conserved in eukaryotes, from yeast to human.
Topics: Animals; DNA Damage; DNA-Binding Proteins; Humans; Mammals; Plants; Proliferating Cell Nuclear Antigen; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Sumoylation; Ubiquitin-Conjugating Enzymes; Ubiquitination
PubMed: 32726436
DOI: 10.1042/BCJ20190579 -
Journal of Medicinal Chemistry Apr 2022Protein -nitrosation (SNO), a posttranslational modification (PTM) of cysteine (Cys) residues elicited by nitric oxide (NO), regulates a wide range of protein functions.... (Review)
Review
Protein -nitrosation (SNO), a posttranslational modification (PTM) of cysteine (Cys) residues elicited by nitric oxide (NO), regulates a wide range of protein functions. As a crucial form of redox-based signaling by NO, SNO contributes significantly to the modulation of physiological functions, and SNO imbalance is closely linked to pathophysiological processes. Site-specific identification of the SNO protein is critical for understanding the underlying molecular mechanisms of protein function regulation. Although careful verification is needed, SNO modification data containing numerous functional proteins are a potential research direction for druggable target identification and drug discovery. Undoubtedly, SNO-related research is meaningful not only for the development of NO donor drugs but also for classic target-based drug design. Herein, we provide a comprehensive summary of SNO, including its origin and transport, identification, function, and potential contribution to drug discovery. Importantly, we propose new views to develop novel therapies based on potential protein SNO-sourced targets.
Topics: Cysteine; Nitric Oxide; Nitrosation; Protein Processing, Post-Translational; Protein S; Proteins
PubMed: 35412827
DOI: 10.1021/acs.jmedchem.1c02194 -
Seminars in Cancer Biology Nov 2022Metabolic reprogramming is an important cancer hallmark that plays a key role in cancer malignancies and therapy resistance. Cancer cells reprogram the metabolic... (Review)
Review
Metabolic reprogramming is an important cancer hallmark that plays a key role in cancer malignancies and therapy resistance. Cancer cells reprogram the metabolic pathways to generate not only energy and building blocks but also produce numerous key signaling metabolites to impact signaling and epigenetic/transcriptional regulation for cancer cell proliferation and survival. A deeper understanding of the mechanisms by which metabolic reprogramming is regulated in cancer may provide potential new strategies for cancer targeting. Recent studies suggest that deregulated transcription factors have been observed in various human cancers and significantly impact metabolism and signaling in cancer. In this review, we highlight the key transcription factors that are involved in metabolic control, dissect the crosstalk between signaling and transcription factors in metabolic reprogramming, and offer therapeutic strategies targeting deregulated transcription factors for cancer treatment.
Topics: Humans; Transcription Factors; Neoplasms; Metabolic Networks and Pathways
PubMed: 36244530
DOI: 10.1016/j.semcancer.2022.10.001 -
The FEBS Journal Feb 2022The lipid post-translational modification S-palmitoylation is a vast developing field, with the modification itself and the enzymes that catalyse the reversible reaction... (Review)
Review
The lipid post-translational modification S-palmitoylation is a vast developing field, with the modification itself and the enzymes that catalyse the reversible reaction implicated in a number of diseases. In this review, we discuss the past and recent advances in the experimental tools used in this field, including pharmacological tools, animal models and techniques to understand how palmitoylation controls protein localisation and function. Additionally, we discuss the obstacles to overcome in order to advance the field, particularly to the point at which modulating palmitoylation may be achieved as a therapeutic strategy.
Topics: Animals; Humans; Lipid Metabolism; Lipids; Lipoylation; Protein S
PubMed: 33624421
DOI: 10.1111/febs.15781 -
Plant & Cell Physiology Jul 2022The thiol group of cysteine (Cys) residues, often present in the active center of the protein, is of particular importance to protein function, which is significantly... (Review)
Review
The thiol group of cysteine (Cys) residues, often present in the active center of the protein, is of particular importance to protein function, which is significantly determined by the redox state of a protein's environment. Our knowledge of different thiol-based oxidative posttranslational modifications (oxiPTMs), which compete for specific protein thiol groups, has increased over the last 10 years. The principal oxiPTMs include S-sulfenylation, S-glutathionylation, S-nitrosation, persulfidation, S-cyanylation and S-acylation. The role of each oxiPTM depends on the redox cellular state, which in turn depends on cellular homeostasis under either optimal or stressful conditions. Under such conditions, the metabolism of molecules such as glutathione, NADPH (reduced nicotinamide adenine dinucleotide phosphate), nitric oxide, hydrogen sulfide and hydrogen peroxide can be altered, exacerbated and, consequently, outside the cell's control. This review provides a broad overview of these oxiPTMs under physiological and unfavorable conditions, which can regulate the function of target proteins.
Topics: Glutathione; Oxidation-Reduction; Oxidative Stress; Plant Proteins; Protein Processing, Post-Translational; Sulfhydryl Compounds
PubMed: 35323963
DOI: 10.1093/pcp/pcac036 -
Current Opinion in Chemical Biology Dec 2021Protein S-fatty acylation or S-palmitoylation is a reversible and regulated lipid post-translational modification (PTM) in eukaryotes. Loss-of-function mutagenesis... (Review)
Review
Protein S-fatty acylation or S-palmitoylation is a reversible and regulated lipid post-translational modification (PTM) in eukaryotes. Loss-of-function mutagenesis studies have suggested important roles for protein S-fatty acylation in many fundamental biological pathways in development, neurobiology, and immunity that are also associated with human diseases. However, the hydrophobicity and reversibility of this PTM have made site-specific gain-of-function studies more challenging to investigate. In this review, we summarize recent chemical biology approaches and methods that have enabled site-specific gain-of-function studies of protein S-fatty acylation and the investigation of the mechanisms and significance of this PTM in eukaryotic biology.
Topics: Acylation; Humans; Lipoylation; Protein Processing, Post-Translational; Protein S
PubMed: 34333222
DOI: 10.1016/j.cbpa.2021.06.004 -
Archives of Biochemistry and Biophysics Dec 2021Ligand-dependent changes in protein conformation are foundational to biology. Historical mechanistic models for substrate-specific proteins are induced fit (IF) and... (Review)
Review
Ligand-dependent changes in protein conformation are foundational to biology. Historical mechanistic models for substrate-specific proteins are induced fit (IF) and conformational selection (CS), which invoke a change in protein conformation after ligand binds or before ligand binds, respectively. These mechanisms have important, but rarely discussed, functional relevance because IF vs. CS can differentially affect a protein's substrate specificity or promiscuity, and its regulatory properties. The modern view of proteins as conformational ensembles in both ligand free and bound states, together with the realization that most proteins exhibit some substrate promiscuity, demands a deeper interpretation of the historical models and provides an opportunity to improve mechanistic analyses. Here we describe alternative analytical strategies for distinguishing the historical models, including the more complex expanded versions of IF and CS. Functional implications of the different models are described. We provide an alternative perspective based on protein ensembles interacting with ligand ensembles that clarifies how a single protein can 'apparently' exploit different mechanisms for different ligands. Mechanistic information about protein ensembles can be optimized when they are probed with multiple ligands.
Topics: Kinetics; Ligands; Protein Binding; Protein Conformation; Proteins; Thermodynamics
PubMed: 34715072
DOI: 10.1016/j.abb.2021.109064 -
Current Opinion in Cell Biology Apr 2021Many cellular processes involve buffering mechanisms against noise to enhance state stability. Such processes include the cell cycle and the switch between respiration... (Review)
Review
Many cellular processes involve buffering mechanisms against noise to enhance state stability. Such processes include the cell cycle and the switch between respiration and fermentation. In recent years, protein aggregation/condensation has emerged as an important regulatory mechanism. In this article, we examine the regulation of Std1, an activator of the Snf1/AMPK kinase, by sequestration into foci of liquid drops, and how foci of metabolic signaling and enzymatic proteins are regulated by chaperones, anti-aggregases and by phosphorylation.
Topics: Glucose; Intracellular Signaling Peptides and Proteins; Phosphorylation; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Signal Transduction
PubMed: 33388622
DOI: 10.1016/j.ceb.2020.12.002