Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.619
Filtrar
1.
Cancer Biol Ther ; 25(1): 2321767, 2024 12 31.
Artigo em Inglês | MEDLINE | ID: mdl-38417050

RESUMO

Doxorubicin (DOX) is one of the most effective and widely used chemotherapeutic drugs. However, DOX resistance is a critical risk problem for breast cancer treatment. Previous studies have demonstrated that metadherin (MTDH) involves in DOX resistance in breast cancer, but the exact mechanism remains unclear. In this study, we found that glutaminyl-peptide cyclotransferase (QPCT) was a MTDH DOX resistance-related downstream gene in breast cancer. Elevated expression of QPCT was found in the GEPIA database, breast cancer tissue, and breast cancer cells. Clinical data showed that QPCT expression was positively associated with poor prognosis in DOX-treated patients. Overexpression of QPCT could promote the proliferation, invasion and migration, and reduce DOX sensitivity in MCF-7 and MDA-MB-231 cells. Mechanistically, MTDH positively regulates the expressions of NF-κB (p65) and QPCT, and NF-κB (p65) directly regulates the expression of QPCT. Therefore, MTDH/NF-κB (p65)/QPCT signal axis was proposed. Collectively, our findings delineate the mechanism by which the MTDH/NF-κB (p65) axis regulate QPCT signaling and suggest that this complex may play an essential role in breast cancer progression and affect DOX sensitivity.


Assuntos
Aminoaciltransferases , Neoplasias da Mama , Humanos , Feminino , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , NF-kappa B/metabolismo , Linhagem Celular Tumoral , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas de Ligação a RNA/genética
2.
Angew Chem Int Ed Engl ; 63(14): e202316777, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38366985

RESUMO

Topological transformations and permutations of proteins have attracted significant interest as strategies to generate new protein functionalities or stability. These efforts have mainly been inspired by naturally occurring post-translational modifications, such as head-to-tail cyclization, circular permutation, or lasso-like entanglement. Such approaches can be realized experimentally via genetic encoding, in the case of circular permutation, or via enzymatic processing, in the case of cyclization. Notably, these previously described strategies leave the polypeptide backbone orientation unaltered. Here we describe an unnatural protein permutation, the protein domain inversion, whereby a C-terminal portion of a protein is enzymatically inverted from the canonical N-to-C to a C-to-C configuration with respect to the N-terminal part of the protein. The closest conceptually analogous biological process is perhaps the inversion of DNA segments as catalyzed by recombinases. We achieve these inversions using an engineered sortase A, a widely used transpeptidase. Our reactions proceed efficiently under mild conditions at 4-25 °C and are compatible with entirely heterologously-produced protein substrates.


Assuntos
Aminoaciltransferases , Peptidil Transferases , Domínios Proteicos , Peptídeos/química , Proteínas de Bactérias/metabolismo , Aminoaciltransferases/química , Peptidil Transferases/metabolismo , DNA , Catálise
3.
Nucleic Acids Res ; 52(5): 2130-2141, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38407292

RESUMO

Outliers in scientific observations are often ignored and mostly remain unreported. However, presenting them is always beneficial since they could reflect the actual anomalies that might open new avenues. Here, we describe two examples of the above that came out of the laboratories of two of the pioneers of nucleic acid research in the area of protein biosynthesis, Paul Berg and Donald Crothers. Their work on the identification of D-aminoacyl-tRNA deacylase (DTD) and 'Discriminator hypothesis', respectively, were hugely ahead of their time and were partly against the general paradigm at that time. In both of the above works, the smallest and the only achiral amino acid turned out to be an outlier as DTD can act weakly on glycine charged tRNAs with a unique discriminator base of 'Uracil'. This peculiar nature of glycine remained an enigma for nearly half a century. With a load of available information on the subject by the turn of the century, our work on 'chiral proofreading' mechanisms during protein biosynthesis serendipitously led us to revisit these findings. Here, we describe how we uncovered an unexpected connection between them that has implications for evolution of different eukaryotic life forms.


Assuntos
Aminoaciltransferases , Eucariotos , Glicina , Biossíntese de Proteínas , Aminoácidos/genética , Aminoaciltransferases/genética , Glicina/genética , Aminoacil-RNA de Transferência/metabolismo , Pesquisa , Bioquímica , Eucariotos/química , Eucariotos/genética
4.
Cell Commun Signal ; 22(1): 87, 2024 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-38297346

RESUMO

BACKGROUND: Arginyltransferase (Ate1) orchestrates posttranslational protein arginylation, a pivotal regulator of cellular proteolytic processes. In eukaryotic cells, two interconnected systems-the ubiquitin proteasome system (UPS) and macroautophagy-mediate proteolysis and cooperate to maintain quality protein control and cellular homeostasis. Previous studies have shown that N-terminal arginylation facilitates protein degradation through the UPS. Dysregulation of this machinery triggers p62-mediated autophagy to ensure proper substrate processing. Nevertheless, how Ate1 operates through this intricate mechanism remains elusive. METHODS: We investigated Ate1 subcellular distribution through confocal microscopy and biochemical assays using cells transiently or stably expressing either endogenous Ate1 or a GFP-tagged Ate1 isoform transfected in CHO-K1 or MEFs, respectively. To assess Ate1 and p62-cargo clustering, we analyzed their colocalization and multimerization status by immunofluorescence and nonreducing immunoblotting, respectively. Additionally, we employed Ate1 KO cells to examine the role of Ate1 in autophagy. Ate1 KO MEFs cells stably expressing GFP-tagged Ate1-1 isoform were used as a model for phenotype rescue. Autophagy dynamics were evaluated by analyzing LC3B turnover and p62/SQSTM1 levels under both steady-state and serum-starvation conditions, through immunoblotting and immunofluorescence. We determined mTORC1/AMPk activation by assessing mTOR and AMPk phosphorylation through immunoblotting, while mTORC1 lysosomal localization was monitored by confocal microscopy. RESULTS: Here, we report a multifaceted role for Ate1 in the autophagic process, wherein it clusters with p62, facilitates autophagic clearance, and modulates its signaling. Mechanistically, we found that cell-specific inactivation of Ate1 elicits overactivation of the mTORC1/AMPk signaling hub that underlies a failure in autophagic flux and subsequent substrate accumulation, which is partially rescued by ectopic expression of Ate1. Statistical significance was assessed using a two-sided unpaired t test with a significance threshold set at P<0.05. CONCLUSIONS: Our findings uncover a critical housekeeping role of Ate1 in mTORC1/AMPk-regulated autophagy, as a potential therapeutic target related to this pathway, that is dysregulated in many neurodegenerative and cancer diseases.


Assuntos
Aminoaciltransferases , Aminoaciltransferases/genética , Aminoaciltransferases/metabolismo , Ubiquitina/metabolismo , Autofagia , Complexo de Endopeptidases do Proteassoma/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina , Isoformas de Proteínas
5.
J Med Chem ; 67(2): 1127-1146, 2024 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-38170998

RESUMO

Sortase A (SrtA) is a membrane-associated cysteine transpeptidase required for bacterial virulence regulation and anchors surface proteins to cell wall, thereby assisting biofilm formation. SrtA is targeted in antivirulence treatments against Gram-positive bacterial infections. However, the development of potent small-molecule SrtA inhibitors is constrained owing to the limited understanding of the mode of action of inhibitors in the SrtA binding pocket. Herein, we designed and synthesized a novel class of covalent SrtA inhibitors based on the binding mode detailed in the X-ray crystal structure of the ML346/Streptococcus pyogenes SrtA complex. ML346 analog Y40 exhibited 2-fold increased inhibitory activity on Staphylococcus aureus SrtA and showed superior inhibitory effects on biofilm formation in vitro. Y40 protected Galleria mellonella larvae fromS. aureusinfections in vivo while minimally attenuating staphylococcal growth in vitro. Our study indicates that the covalent SrtA inhibitor Y40 is an antivirulence agent that is effective againstS. aureusinfections.


Assuntos
Aminoaciltransferases , Staphylococcus aureus , Proteínas de Bactérias , Cisteína Endopeptidases/metabolismo
6.
Biopolymers ; 115(1): e23539, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37227047

RESUMO

Many species of pathogenic gram-positive bacteria display covalently crosslinked protein polymers (called pili or fimbriae) that mediate microbial adhesion to host tissues. These structures are assembled by pilus-specific sortase enzymes that join the pilin components together via lysine-isopeptide bonds. The archetypal SpaA pilus from Corynebacterium diphtheriae is built by the Cd SrtA pilus-specific sortase, which crosslinks lysine residues within the SpaA and SpaB pilins to build the shaft and base of the pilus, respectively. Here, we show that Cd SrtA crosslinks SpaB to SpaA via a K139(SpaB)-T494(SpaA) lysine-isopeptide bond. Despite sharing only limited sequence homology, an NMR structure of SpaB reveals striking similarities with the N-terminal domain of SpaA (N SpaA) that is also crosslinked by Cd SrtA. In particular, both pilins contain similarly positioned reactive lysine residues and adjacent disordered AB loops that are predicted to be involved in the recently proposed "latch" mechanism of isopeptide bond formation. Competition experiments using an inactive SpaB variant and additional NMR studies suggest that SpaB terminates SpaA polymerization by outcompeting N SpaA for access to a shared thioester enzyme-substrate reaction intermediate.


Assuntos
Aminoaciltransferases , Corynebacterium diphtheriae , Proteínas de Fímbrias/química , Proteínas de Fímbrias/metabolismo , Corynebacterium diphtheriae/metabolismo , Proteínas de Bactérias/metabolismo , Lisina , Cádmio/metabolismo , Aminoaciltransferases/metabolismo
7.
J Biomol Struct Dyn ; 42(3): 1157-1169, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37184111

RESUMO

Staphylococcus aureus is a prevalent Gram-positive bacteria leading cause of a wide range of human pathologies. Moreover, antibiotic résistance of pathogenesis bacteria is one of the worldwide health problems. In Gram-positive bacteria, the enzyme of SrtA, is responsible for the anchoring of surface-exposed proteins to the cell wall peptidoglycan. Because of its critical role in Gram-positive bacterial pathogenesis, SrtA is an attractive target for anti-virulence during drug development. To date, some SrtA inhibitors have been discovered most of them being derived from flavonoid compounds, like Myricetin. In order to provide potential hit molecules against SrtA for clinical use, we obtained a total of 293 compounds by performing in silico shape-based screening of compound libraries against Myristin as a reference structure. Employing molecular docking and scoring functions, the top 3 compounds Apigenin, Efloxate, and Compound 8261032 were screened by comparing their docking scores with Myricetin. Furthermore, MD simulations and MM-PBSA binding energy calculation studies revealed that only Compound 8261032 strongly binds to the catalytic core of the SrtA enzyme than Myricetin, and stable behavior was consistently observed in the docking complex. Compound 8261032 showed a good number of hydrogen bonds with SrtA and higher MM-PBSA binding energy when compared to all three molecules. Also, it makes strength interactions with Arg139 and His62, which are critical for SrtA biological activity. This study showed that the development of this inhibitor could be a fundamental strategy against resistant bacteria, but further studies in vitro are needed to confirm this claim.Communicated by Ramaswamy H. Sarma.


Assuntos
Aminoaciltransferases , Cisteína Endopeptidases , Staphylococcus aureus , Humanos , Simulação de Dinâmica Molecular , Simulação de Acoplamento Molecular , Proteínas de Bactérias/química , Aminoaciltransferases/química
8.
Angew Chem Int Ed Engl ; 63(8): e202310862, 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38072831

RESUMO

Quantitative and selective labelling of proteins is widely used in both academic and industrial laboratories, and catalytic labelling of proteins using transpeptidases, such as sortases, has proved to be a popular strategy for such selective modification. A major challenge for this class of enzymes is that the majority of procedures require an excess of the labelling reagent or, alternatively, activated substrates rather than simple commercially sourced peptides. We report the use of a coupled enzyme strategy which enables quantitative N- and C-terminal labelling of proteins using unactivated labelling peptides. The use of an aminopeptidase in conjunction with a transpeptidase allows sequence-specific degradation of the peptide by-product, shifting the equilibrium to favor product formation, which greatly enhances the reaction efficiency. Subsequent optimisation of the reaction allows N-terminal labelling of proteins using essentially equimolar ratios of peptide label to protein and C-terminal labelling with only a small excess. Minimizing the amount of substrate required for quantitative labelling has the potential to improve industrial processes and facilitate the use of transpeptidation as a method for protein labelling.


Assuntos
Aminoaciltransferases , Peptidil Transferases , Aminopeptidases , Proteínas de Bactérias/metabolismo , Aminoaciltransferases/metabolismo , Peptídeos/metabolismo
9.
J Antimicrob Chemother ; 79(2): 403-411, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38153239

RESUMO

BACKGROUND: Streptococcus suis is an important pig pathogen and an emerging zoonotic agent. In a previous study, we described a high proportion of penicillin-resistant serotype 9 S. suis (SS9) isolates on pig farms in Italy. OBJECTIVES: We hypothesized that resistance to penicillin emerged in some SS9 lineages characterized by substitutions at the PBPs, contributing to the successful spread of these lineages in the last 20 years. METHODS: Sixty-six SS9 isolates from cases of streptococcosis in pigs were investigated for susceptibility to penicillin, ceftiofur and ampicillin. The isolates were characterized for ST, virulence profile, and antimicrobial resistance genes through WGS. Multiple linear regression models were employed to investigate the associations between STs, year of isolation, substitutions at the PBPs and an increase in MIC values to ß-lactams. RESULTS: MIC values to penicillin increased by 4% each year in the study period. Higher MIC values for penicillin were also positively associated with ST123, ST1540 and ST1953 compared with ST16. The PBP sequences presented a mosaic organization of blocks. Within the same ST, substitutions at the PBPs were generally more frequent in recent isolates. Resistance to penicillin was driven by substitutions at PBP2b, including K479T, D512E and K513E, and PBP2x, including T551S, while reduced susceptibility to ceftiofur and ampicillin were largely dependent on substitutions at PBP2x. CONCLUSIONS: Here, we identify the STs and substitutions at the PBPs responsible for increased resistance of SS9 to penicillin on Italian pig farms. Our data highlight the need for monitoring the evolution of S. suis in the coming years.


Assuntos
Aminoaciltransferases , Cefalosporinas , Streptococcus suis , Animais , Suínos , Penicilinas/farmacologia , Proteínas de Ligação às Penicilinas/genética , Streptococcus suis/genética , Proteínas de Bactérias/genética , Streptococcus pneumoniae/genética , Sorogrupo , Aminoaciltransferases/genética , Testes de Sensibilidade Microbiana , Resistência às Penicilinas/genética , Genômica , Ampicilina , Células Clonais , Antibacterianos/farmacologia
10.
Bioorg Med Chem ; 97: 117542, 2024 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-38104495

RESUMO

Glutaminyl cyclase (QC) plays a crucial role in the early stages of Alzheimer's disease (AD), thus inhibition of QC may be a promising strategy for the treatment of early AD. Therefore, QC inhibitors with novel chemical scaffolds may contribute to the development of additional anti-AD agents. We conducted a virtual screening of 3 million compounds from the Chemdiv and Enamine databases, to discover potential scaffolds for QC inhibitors. Three scaffolds, 120974, 147706, and 141449, were selected from this structure-based virtual screening through a combination of pharmacophore modeling, a receptor-ligand pharmacophore model, and the GALAHAD model, and furtherly filtered by chelation with zinc ion and docking properties. Consequently, three compounds, 1, 2, and 3, were designed and synthesized based on these three scaffolds, respectively. The IC50 of compounds 1 and 3 against QC were 14.19 ± 4.21 and 4.34 ± 0.35 µM, respectively. Our results indicate that the new scaffolds selected using a virtual screening process exhibit potential as novel QC inhibitors.


Assuntos
Doença de Alzheimer , Aminoaciltransferases , Humanos , Aminoaciltransferases/antagonistas & inibidores , Aminoaciltransferases/química , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Simulação de Acoplamento Molecular
12.
Mol Cell Proteomics ; 22(11): 100664, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37832787

RESUMO

Arginylation is a post-translational modification mediated by the arginyltransferase 1 (ATE1), which transfers the amino acid arginine to a protein or peptide substrate from a tRNA molecule. Initially, arginylation was thought to occur only on N-terminally exposed acidic residues, and its function was thought to be limited to targeting proteins for degradation. However, more recent data have shown that ATE1 can arginylate side chains of internal acidic residues in a protein without necessarily affecting metabolic stability. This greatly expands the potential targets and functions of arginylation, but tools for studying this process have remained limited. Here, we report the first global screen specifically for side-chain arginylation. We generate and validate "pan-arginylation" antibodies, which are designed to detect side-chain arginylation in any amino acid sequence context. We use these antibodies for immunoaffinity enrichment of side-chain arginylated proteins from wildtype and Ate1 knockout cell lysates. In this way, we identify a limited set of proteins that likely undergo ATE1-dependent side-chain arginylation and that are enriched in specific cellular roles, including translation, splicing, and the cytoskeleton.


Assuntos
Aminoaciltransferases , Aminoaciltransferases/metabolismo , Proteínas/metabolismo , Peptídeos/metabolismo , Processamento de Proteína Pós-Traducional , Sequência de Aminoácidos , Anticorpos/metabolismo , Arginina/metabolismo
13.
Nat Commun ; 14(1): 5520, 2023 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-37684232

RESUMO

Many eukaryotic receptors and enzymes rely on glycosylphosphatidylinositol (GPI) anchors for membrane localization and function. The transmembrane complex GPI-T recognizes diverse proproteins at a signal peptide region that lacks consensus sequence and replaces it with GPI via a transamidation reaction. How GPI-T maintains broad specificity while preventing unintentional cleavage is unclear. Here, substrates- and products-bound human GPI-T structures identify subsite features that enable broad proprotein specificity, inform catalytic mechanism, and reveal a multilevel safeguard mechanism against its promiscuity. In the absence of proproteins, the catalytic site is invaded by a locally stabilized loop. Activation requires energetically unfavorable rearrangements that transform the autoinhibitory loop into crucial catalytic cleft elements. Enzyme-proprotein binding in the transmembrane and luminal domains respectively powers the conformational rearrangement and induces a competent cleft. GPI-T thus integrates various weak specificity regions to form strong selectivity and prevent accidental activation. These findings provide important mechanistic insights into GPI-anchored protein biogenesis.


Assuntos
Aminoaciltransferases , Glicosilfosfatidilinositóis , Humanos , Catálise , Domínio Catalítico , Ligantes
14.
mBio ; 14(5): e0098023, 2023 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-37750700

RESUMO

IMPORTANCE: Exclusively in the Bacteroidetes phylum, most proteins exported across the inner membrane via the Sec system and released into the periplasm by type I signal peptidase have N-terminal glutamine converted to pyroglutamate. The reaction is catalyzed by the periplasmic enzyme glutaminyl cyclase (QC), which is essential for the growth of Porphyromonas gingivalis and other periodontopathogens. Apparently, pyroglutamyl formation stabilizes extracytoplasmic proteins and/or protects them from proteolytic degradation in the periplasm. Given the role of P. gingivalis as the keystone pathogen in periodontitis, P. gingivalis QC is a promising target for the development of drugs to treat and/or prevent this highly prevalent chronic inflammatory disease leading to tooth loss and associated with severe systemic diseases.


Assuntos
Aminoaciltransferases , Periodontite , Humanos , Aminoaciltransferases/genética , Aminoaciltransferases/metabolismo , Ácido Pirrolidonocarboxílico/metabolismo , Glutamina
15.
Bioorg Med Chem Lett ; 93: 129428, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-37541632

RESUMO

Imaging or killing of a specific pathogen is of significance for precise therapy. Staphylococcus aureus (S. aureus) is an infectious gram-positive bacteria relying on Sortase A (SrtA) to anchor cell surface protein on peptidoglycan. We herein report signal-on labeling of S. aureus with self-quenched optical probes featuring vancomycin-conjugated SrtA substrate that is flanked by a dabcyl moiety paired with either fluorescein or eosine photosensizer (PS). SrtA-mediated cleavage of the substrate motif releases the dabcyl quencher, leading to covalent labeling of peptidoglycan with fluorescein or PS of restored photophysical property. The dual biomarked-enabled peptidoglycan labeling enables signal-on imaging and effective photodynamic destruction of S. aureus, suggesting a protheranostic approch activatable to SrtA-positive bacteria engaged in myriad diseases.


Assuntos
Aminoaciltransferases , Staphylococcus aureus , Staphylococcus aureus/metabolismo , Peptidoglicano/metabolismo , Proteínas de Bactérias/metabolismo , Aminoaciltransferases/metabolismo , Proteínas de Membrana/metabolismo , Fluoresceínas
16.
Bioconjug Chem ; 34(9): 1667-1678, 2023 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-37534819

RESUMO

Conferring multifunctional properties to proteins via enzymatic approaches has greatly facilitated recent progress in protein nanotechnology. In this regard, sortase (Srt) A transpeptidation has facilitated many of these developments due to its exceptional specificity, mild reaction conditions, and complementation with other bioorthogonal techniques, such as click chemistry. In most of these developments, Srt A is used to seamlessly tether oligoglycine-containing molecules to a protein of interest that is equipped with the enzyme's recognition sequence, LPXTG. However, the dependence on oligoglycine attacking nucleophiles and the associated cost of certain derivatives (e.g., cyclooctyne) limit the utility of this approach to lab-scale applications only. Thus, the quest to identify appropriate alternatives and understand their effectiveness remains an important area of research. This study identifies that steric and nucleophilicity-associated effects influence Srt A transpeptidation when two oligoglycine surrogates were examined. The approach was further used in complementation with click chemistry to synthesize bivalent and bifunctional nanobody conjugates for application in epithelial growth factor receptor targeting. The overall technique and tools developed here may facilitate the advancement of future nanotechnologies.


Assuntos
Aminoaciltransferases , Química Click , Proteínas de Bactérias/química , Aminoaciltransferases/metabolismo , Cisteína Endopeptidases/metabolismo
17.
Int J Biol Macromol ; 243: 125183, 2023 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-37276901

RESUMO

Dental plaque is a complex microbial biofilm community of many species and a major cause of oral infections and infectious endocarditis. Plaque development begins when primary colonizers attach to oral tissues and undergo coaggregation. Primary colonizers facilitate cellular attachment and inter-bacterial interactions through sortase-dependent pili (or fimbriae) extending out from their cell surface. Consequently, the sortase enzyme is viewed as a potential drug target for controlling biofilm formation and avoiding infection. Streptococcus sanguinis is a primary colonizing bacterium whose pili consist of three different pilin subunits that are assembled together by the pilus-specific (C-type) SsaSrtC sortase. Here, we report on the crystal structure determination of the recombinant wild-type and active-site mutant forms of SsaSrtC. Interestingly, the SsaSrtC structure exhibits an open-lid conformation, although a conserved DPX motif is lacking in the lid. Based on molecular docking and structural analysis, we identified the substrate-binding residues essential for pilin recognition and pilus assembly. We also demonstrated that while recombinant SsaSrtC is enzymatically active toward the five-residue LPNTG sorting motif peptide of the pilins, this activity is significantly reduced by the presence of zinc. We further showed that rutin and α-crocin are potential candidate inhibitors of the SsaSrtC sortase via structure-based virtual screening and inhibition assays. The structural knowledge gained from our study will provide the means to develop new approaches that target pilus-mediated attachment, thereby preventing oral biofilm growth and infection.


Assuntos
Aminoaciltransferases , Proteínas de Fímbrias , Proteínas de Fímbrias/genética , Proteínas de Fímbrias/química , Proteínas de Fímbrias/metabolismo , Proteínas de Bactérias/química , Streptococcus sanguis/metabolismo , Simulação de Acoplamento Molecular , Aminoaciltransferases/química
18.
Org Lett ; 25(26): 4857-4861, 2023 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-37358473

RESUMO

We have described the chemical synthesis of d-Sortase A in large quantity and high purity by a hydrazide ligation strategy. The d-Sortase was fully active toward d-peptides and D/L hybrid proteins, and the ligation efficiency was unaffected by the chirality of the C-terminus substrate. This study points toward using d-sortase ligation as a modern ligation method for d-proteins and D/L hybrid proteins and expands the chemical protein synthesis toolbox in biotechnology.


Assuntos
Aminoaciltransferases , Peptídeos , Proteínas de Bactérias/metabolismo , Aminoaciltransferases/metabolismo
19.
Drug Discov Today ; 28(10): 103644, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37244566

RESUMO

Glutaminyl cyclase (QC) activity has been identified as a key effector in distinct biological processes. Human glutaminyl-peptide cyclotransferase (QPCT) and glutaminyl-peptide cyclotransferase-like (QPCTL) are considered attractive therapeutic targets in many human disorders, such as neurodegenerative diseases, and a range of inflammatory conditions, as well as for cancer immunotherapy, because of their capacity to modulate cancer immune checkpoint proteins. In this review, we explore the biological functions and structures of QPCT/L enzymes and highlight their therapeutic relevance. We also summarize recent developments in the discovery of small-molecule inhibitors targeting these enzymes, including an overview of preclinical and clinical studies.


Assuntos
Doença de Alzheimer , Aminoaciltransferases , Neoplasias , Humanos , Imunoterapia , Doença de Alzheimer/tratamento farmacológico
20.
Bioconjug Chem ; 34(6): 1114-1121, 2023 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-37246906

RESUMO

Enzymes are of central importance to many biotechnological and biomedical applications. However, for many potential applications, the required conditions impede enzyme folding and therefore function. The enzyme Sortase A is a transpeptidase that is widely used to perform bioconjugation reactions with peptides and proteins. Thermal and chemical stress impairs Sortase A activity and prevents its application under harsh conditions, thereby limiting the scope for bioconjugation reactions. Here, we report the stabilization of a previously reported, activity-enhanced Sortase A, which suffered from particularly low thermal stability, using the in situ cyclization of proteins (INCYPRO) approach. After introduction of three spatially aligned solvent-exposed cysteines, a triselectrophilic cross-linker was attached. The resulting bicyclic INCYPRO Sortase A demonstrated activity both at elevated temperature and in the presence of chemical denaturants, conditions under which both wild-type Sortase A and the activity-enhanced version are inactive.


Assuntos
Aminoaciltransferases , Proteínas de Bactérias , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Aminoaciltransferases/metabolismo , Peptídeos , Cisteína Endopeptidases/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...