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Biochemical Pharmacology Nov 2023GPR81, initially discovered in adipocytes, has been found to suppress lipolysis when activated. However, the current small molecules that target GPR81 carry the risk of...
GPR81, initially discovered in adipocytes, has been found to suppress lipolysis when activated. However, the current small molecules that target GPR81 carry the risk of off-target effects, and their impact on tumor progression remains uncertain. Here, we utilized phage display technology to screen a GPR81-targeting peptide named 7w-2 and proceeded to demonstrate its bioactivity. Although 7w-2 did not affect the proliferation of tumor cells, it effectively reduced adipocyte catabolism in vitro, consequently restraining the proliferation of co-cultured tumor cells. Furthermore, our findings revealed that 7w-2 could inhibit lipolysis in vivo, leading to a significant impediment in tumor growth and metastasis in the 4T1 murine tumor model. Additionally, 7w-2 exhibited the ability to significantly elevate the proportion and functionality of CD8 T cells. Our study introduces 7w-2 as the first peptide targeting GPR81, shedding light on its potential role in adipocytes in suppressing tumor progression.
Topics: Mice; Animals; Receptors, G-Protein-Coupled; CD8-Positive T-Lymphocytes; Adipocytes; Lipolysis; Peptides
PubMed: 37696459
DOI: 10.1016/j.bcp.2023.115800 -
Current Opinion in Plant Biology Oct 2023Proteinogenic dipeptides, with few known exceptions, are products of protein degradation. Dipeptide levels respond to the changes in the environment, often in a... (Review)
Review
Proteinogenic dipeptides, with few known exceptions, are products of protein degradation. Dipeptide levels respond to the changes in the environment, often in a dipeptide-specific manner. What drives this specificity is currently unknown; what likely contributes is the activity of the different peptidases that cleave off the terminal dipeptide from the longer peptides. Dipeptidases that degrade dipeptides to amino acids, and the turnover rates of the "substrate" proteins/peptides. Plants can both uptake dipeptides from the soil, but dipeptides are also found in root exudates. Dipeptide transporters, members of the proton-coupled peptide transporters NTR1/PTR family, contribute to nitrogen reallocation between the sink and source tissues. Besides their role in nitrogen distribution, it becomes increasingly clear that dipeptides may also serve regulatory, dipeptide-specific functions. Dipeptides are found in protein complexes affecting the activity of their protein partners. Moreover, dipeptide supplementation leads to cellular phenotypes reflected in changes in plant growth and stress tolerance. Herein we will review the current understanding of dipeptides' metabolism, transport, and functions and discuss significant challenges and future directions for the comprehensive characterization of this fascinating but underrated group of small-molecule compounds.
Topics: Dipeptides; Biological Transport; Amino Acids; Nitrogen
PubMed: 37311365
DOI: 10.1016/j.pbi.2023.102395 -
Biochemical Society Transactions Feb 2024Histone deacylases are erasers of Nε-acyl-lysine post-translational modifications and have been targeted for decades for the treatment of cancer, neurodegeneration and... (Review)
Review
Histone deacylases are erasers of Nε-acyl-lysine post-translational modifications and have been targeted for decades for the treatment of cancer, neurodegeneration and other disorders. Due to their relatively promiscuous activity on peptide substrates in vitro, it has been challenging to determine the individual targets and substrate identification mechanisms of each isozyme, and they have been considered redundant regulators. In recent years, biochemical and biophysical studies have incorporated the use of reconstituted nucleosomes, which has revealed a diverse and complex arsenal of recognition mechanisms by which histone deacylases may differentiate themselves in vivo. In this review, we first present the peptide-based tools that have helped characterize histone deacylases in vitro to date, and we discuss the new insights that nucleosome tools are providing into their recognition of histone substrates within chromatin. Then, we summarize the powerful semi-synthetic approaches that are moving forward the study of chromatin-associated factors, both in vitro by detailed single-molecule mechanistic studies, and in cells by live chromatin modification. We finally offer our perspective on how these new techniques would advance the study of histone deacylases. We envision that such studies will help elucidate the role of individual isozymes in disease and provide a platform for the development of the next generation of therapeutics.
Topics: Histones; Chromatin; Nucleosomes; Protein Processing, Post-Translational; Peptides; Acetylation
PubMed: 38189424
DOI: 10.1042/BST20230693 -
Chembiochem : a European Journal of... Sep 2023The late-stage functionalization of peptides and proteins holds significant promise for drug discovery and facilitates bioorthogonal chemistry. This selective... (Review)
Review
The late-stage functionalization of peptides and proteins holds significant promise for drug discovery and facilitates bioorthogonal chemistry. This selective functionalization leads to innovative advances in in vitro and in vivo biological research. However, it is a challenging endeavor to selectively target a certain amino acid or position in the presence of other residues containing reactive groups. Biocatalysis has emerged as a powerful tool for selective, efficient, and economical modifications of molecules. Enzymes that have the ability to modify multiple complex substrates or selectively install nonnative handles have wide applications. Herein, we highlight enzymes with broad substrate tolerance that have been demonstrated to modify a specific amino acid residue in simple or complex peptides and/or proteins at late-stage. The different substrates accepted by these enzymes are mentioned together with the reported downstream bioorthogonal reactions that have benefited from the enzymatic selective modifications.
Topics: Catalysis; Proteins; Peptides; Amino Acids; Biocatalysis
PubMed: 37338668
DOI: 10.1002/cbic.202300372 -
Journal of the American Chemical Society Dec 2023Postsynthetic diversification of peptides through selective modification of endogenous amino acid side chains has enabled significant advances in peptide drug discovery...
Postsynthetic diversification of peptides through selective modification of endogenous amino acid side chains has enabled significant advances in peptide drug discovery while expanding the biological and medical chemistry space. However, current tools have been focused on the modification of reactive polar and ionizable side chains, whereas the decoration of aromatic systems (e.g., the of the tryptophan) has been a long-standing challenge. Here, we introduce metallaphotocatalysis in solid-phase peptide synthesis for the on-resin orthogonal -arylation of relevant tryptophan-containing peptides. The protocol allows the chemoselective introduction of a new C(sp)-N bond at the of tryptophan in biologically active protected peptide sequences in the presence of native redox-sensitive side chains. The fusion of metallaphotocatalysis with solid-phase peptide synthesis opens new perspectives in diversifying native amino acid side chains.
Topics: Tryptophan; Peptides; Amino Acids; Oxidation-Reduction; Solid-Phase Synthesis Techniques
PubMed: 37976043
DOI: 10.1021/jacs.3c10792 -
Organic & Biomolecular Chemistry Oct 2023Cyclic depsipeptides are an important class of peptide natural products that are defined by the presence of ester and amide bonds within the macrocycle. The structural... (Review)
Review
Cyclic depsipeptides are an important class of peptide natural products that are defined by the presence of ester and amide bonds within the macrocycle. The structural diversity of depsipeptides has required the development of a broad range of synthetic strategies to access these biologically active compounds. Solid phase peptide synthesis (SPPS) strategies have been an invaluable tool in their synthesis. The key aspect of their synthesis is the macrocyclization strategy. Three main strategies are used, solution phase macrolactamization of acyclic ester containing peptide, on-resin macrolactamization of a sidechain-anchored peptide, and the solution phase macrolactonization of a linear peptide. Additionally, biocatalysts have been used to produce these compounds in a regio- and chemo-selective manner. Each compound offers unique challenges, requiring careful synthetic design to avoid undesirable side reactivity or unwanted epimerization during the esterification and macrocyclizing steps. This focused review analyzes these three strategies for cyclic depsipeptide natural product total synthesis with selected examples from the literature between 2001-2023.
Topics: Depsipeptides; Molecular Structure; Esterification; Esters; Peptides, Cyclic
PubMed: 37750186
DOI: 10.1039/d3ob01229h -
International Journal of Molecular... Jul 2023Thyrotropin-releasing hormone (TRH) is a tripeptide that regulates the neuroendocrine thyroid axis. Moreover, its widespread brain distribution has indicated that it is... (Review)
Review
Thyrotropin-releasing hormone (TRH) is a tripeptide that regulates the neuroendocrine thyroid axis. Moreover, its widespread brain distribution has indicated that it is a relevant neuromodulator of behaviors such as feeding, arousal, anxiety, and locomotion. Importantly, it is also a neurotrophic peptide, and thus may halt the development of neurodegenerative diseases and improve mood-related disorders. Its neuroprotective actions on those pathologies and behaviors have been limited due to its poor intestinal and blood-brain barrier permeability, and because it is rapidly degraded by a serum enzyme. As new strategies such as TRH intranasal delivery emerge, a renewed interest in the peptide has arisen. TRH analogs have proven to be safe in animals and humans, while not inducing alterations in thyroid hormones' levels. In this review, we integrate research from different approaches, aiming to demonstrate the therapeutic effects of TRH, and to summarize new efforts to prolong and facilitate the peptide's actions to improve symptoms and the progression of several pathologies.
Topics: Animals; Humans; Thyrotropin-Releasing Hormone; Brain; Thyroid Gland; Peptides; Thyroid Hormones
PubMed: 37446225
DOI: 10.3390/ijms241311047 -
Biotechnology and Bioengineering Dec 2023Cytochrome P450s belong to a family of heme-binding monooxygenases, which catalyze regio- and stereospecific functionalisation of C-H, C-C, and C-N bonds, including... (Review)
Review
Cytochrome P450s belong to a family of heme-binding monooxygenases, which catalyze regio- and stereospecific functionalisation of C-H, C-C, and C-N bonds, including heteroatom oxidation, oxidative C-C bond cleavages, and nitrene transfer. P450s are considered useful biocatalysts for the production of pharmaceutical products, fine chemicals, and bioremediating agents. Despite having tremendous biotechnological potential, being heme-monooxygenases, P450s require either autologous or heterologous redox partner(s) to perform chemical transformations. Randomly distributed P450s throughout a bacterial genome and devoid of particular redox partners in natural products biosynthetic gene clusters (BGCs) showed an extra challenge to reveal their pharmaceutical potential. However, continuous efforts have been made to understand their involvement in antibiotic biosynthesis and their modification, and this review focused on such BGCs. Here, particularly, we have discussed the role of P450s involved in the production of macrolides and aminocoumarin antibiotics, nonribosomal peptide (NRPSs) antibiotics, ribosomally synthesized and post-translationally modified peptide (RiPPs) antibiotics, and others. Several reactions catalyzed by P450s, as well as the role of their redox partners involved in the BGCs of various antibiotics and their derivatives, have been primarily addressed in this review, which would be useful in further exploration of P450s for the biosynthesis of new therapeutics.
Topics: Cytochrome P-450 Enzyme System; Oxidation-Reduction; Biocatalysis; Heme; Peptides
PubMed: 37691185
DOI: 10.1002/bit.28548 -
Analytical Chemistry Dec 2023α-Synuclein is an intrinsically disordered protein that plays a critical role in the pathogenesis of neurodegenerative disorders, such as Parkinson's disease....
α-Synuclein is an intrinsically disordered protein that plays a critical role in the pathogenesis of neurodegenerative disorders, such as Parkinson's disease. Proteomics studies of human brain samples have associated the modification of the O-linked -acetyl-glucosamine (O-GlcNAc) to several synucleinopathies; in particular, the position of the O-GlcNAc can regulate protein aggregation and subsequent cell toxicity. There is a need for site specific O-GlcNAc α-synuclein screening tools to direct better therapeutic strategies. In the present work, for the first time, the potential of fast, high-resolution trapped ion mobility spectrometry (TIMS) preseparation in tandem with mass spectrometry assisted by an electromagnetostatic (EMS) cell, capable of electron capture dissociation (ECD), and ultraviolet photodissociation (213 nm UVPD) is illustrated for the characterization of α-synuclein positional glycoforms: T72, T75, T81, and S87 modified with a single O-GlcNAc. Top-down 213 nm UVPD and ECD MS/MS experiments of the intact proteoforms showed specific product ions for each α-synuclein glycoforms associated with the O-GlcNAc position with a sequence coverage of ∼68 and ∼82%, respectively. TIMS-MS profiles of α-synuclein and the four glycoforms exhibited large structural heterogeneity and signature patterns across the 8+-15+ charge state distribution; however, while the α-synuclein positional glycoforms showed signature mobility profiles, they were only partially separated in the mobility domain. Moreover, a middle-down approach based on the Val40-Phe94 (55 residues) chymotrypsin proteolytic product using tandem TIMS-q-ECD-TOF MS/MS permitted the separation of the parent positional isomeric glycoforms. The ECD fragmentation of the ion mobility and / separated isomeric Val40-Phe94 proteolytic peptides with single O-GlcNAc in the T72, T75, T81, and S87 positions provided the O-GlcNAc confirmation and positional assignment with a sequence coverage of ∼80%. This method enables the high-throughput screening of positional glycoforms and further enhances the structural mass spectrometry toolbox with fast, high-resolution mobility separations and 213 nm UVPD and ECD fragmentation capabilities.
Topics: Humans; alpha-Synuclein; Tandem Mass Spectrometry; Parkinson Disease; Peptides; Proteolysis; Peptide Hydrolases
PubMed: 38047498
DOI: 10.1021/acs.analchem.3c02405 -
The Journal of Biological Chemistry Oct 2023Family B2 or adhesion G protein-coupled receptors (AGPCRs) are distinguished by variable extracellular regions that contain a modular protease, termed the GPCR...
Family B2 or adhesion G protein-coupled receptors (AGPCRs) are distinguished by variable extracellular regions that contain a modular protease, termed the GPCR autoproteolysis-inducing domain that self-cleaves the receptor into an N-terminal fragment (NTF) and a C-terminal fragment (CTF), or seven transmembrane domain (7TM). The NTF and CTF remain bound after cleavage through noncovalent interactions. NTF binding to a ligand(s) presented by nearby cells, or the extracellular matrix anchors the NTF, such that cell movement generates force to induce NTF/CTF dissociation and expose the AGPCR tethered peptide agonist. The released tethered agonist (TA) binds rapidly to the 7TM orthosteric site to activate signaling. The orphan AGPCR, GPR114 was reported to be uncleaved, yet paradoxically capable of activation by its TA. GPR114 has an identical cleavage site and TA to efficiently cleave GPR56. Here, we used immunoblotting and biochemical assays to demonstrate that GPR114 is a cleaved receptor, and the self-cleavage is required for GPR114 TA-activation of Gs and no other classes of G proteins. Mutagenesis studies defined features of the GPR114 and GPR56 GAIN subdomains that influenced self-cleavage efficiency. Thrombin treatment of protease-activated receptor 1 leader/AGPCR fusion proteins demonstrated that acute decryption of the GPR114/56 TAs activated signaling. GPR114 was found to be expressed in an eosinophilic-like cancer cell line (EoL-1 cells) and endogenous GPR114 was efficiently self-cleaved. Application of GPR114 TA peptidomimetics to EoL-1 cells stimulated cAMP production. Our findings may aid future delineation of GPR114 function in eosinophil cAMP signaling related to migration, chemotaxis, or degranulation.
Topics: Cell Adhesion; Peptides; Protein Binding; Protein Domains; Receptors, G-Protein-Coupled; Signal Transduction; Humans
PubMed: 37673336
DOI: 10.1016/j.jbc.2023.105223