Tyrosine phosphorylation is one of the important protein phosphorylations in eukaryotes responsible for a variety of biological processes including cell signaling transduction, cell migration, and apoptosis. In the study of phosphoproteomics, due to the low stoichiometry of tyrosine phosphorylation (pTyr) proteins and sometimes limited initial sample, traditional phosphoproteomics enrichment technology is inefficient for the enrichment of pTyr peptides. Here, we review the substantial progress in tyrosine phosphoproteomics by preparation of limited amount sample and the newly introduced SH2 superbinder.
Cell Movement ; Peptides ; Phosphorylation ; Technology ; Tyrosine/metabolism*

Candida albicans is one of the major causes of invasive fungal infections and a serious opportunistic pathogen in immunocompromised individuals. The antimicrobial peptide AMP-17 has prominent anti-Candida activity, and proteomic analysis revealed significant differences in the expression of cell wall (XOG1) and oxidative stress (SRR1) genes upon the action of AMP-17 on C. albicans, suggesting that AMP-17 may exert anti-C. albicans effects by affecting the expression of XOG1 and SRR1 genes. To further investigate whether XOG1 and SRR1 genes were the targets of AMP-17, C. albicans xog1Δ/Δ and srr1Δ/Δ mutants were constructed using the clustered regulatory interspaced short palindromic repeats-associated protein 9 (CRISPR/Cas9) system. Phenotypic observations revealed that deletion of two genes had no significant effect on C. albicans growth and biofilm formation, whereas XOG1 gene deletion affected in vitro stress response and mycelium formation of C. albicans. Drug sensitivity assay showed that the MIC₈₀ values of AMP-17 against xog1Δ/Δ and srr1Δ/Δ mutants increased from 8 μg/mL (for the wild type C. albicans SC5314) to 16 μg/mL, while the MIC₈₀ values against srr1Δ/Δ: : srr1 revertants decreased to the level of the wild type SC5314. In addition, the ability of AMP-17 to inhibit biofilm formation of both deletion strains was significantly reduced compared to that of wild type SC5314, indicating that the susceptibility of the deletion mutants to AMP-17 was reduced in both the yeast state and during biofilm formation. These results suggest that XOG1 and SRR1 genes are likely two of the potential targets for AMP-17 to exert anti-C. albicans effects, which may facilitate further exploration of the antibacterial mechanism of novel peptide antifungal drugs.
Humans ; Candida albicans ; Antimicrobial Peptides ; Proteomics ; Peptides/pharmacology* ; Transcription Factors/metabolism* ; Antifungal Agents/pharmacology*

OBJECTIVE: To describe the global profiles of acetylated proteins in the brains of scrapie agents 139A- and ME7-infected mice collected at mid-early, mid-late, and terminal stages. METHODS: The acetylated proteins from the cortex regions of scrapie agent (139A- and ME7)-infected mice collected at mid-early (80 days postinfection, dpi), mid-late (120 dpi), and terminal (180 dpi) stages were extracted, and the global profiles of brain acetylated proteins were assayed with proteomic mass spectrometry. The proteins in the infected mice showing 1.5-fold higher or lower levels than that of age-matched normal controls were considered as differentially expressed acetylated peptides (DEAPs). RESULTS: A total of 118, 42, and 51 DEAPs were found in the brains of 139A-80, 139A-120, and 139A-180 dpi mice, respectively. Meanwhile, 390, 227, and 75 DEAPs were detected in the brains of ME7-80, ME7-120, and ME7-180 dpi mice, respectively. The overwhelming majority of DEAPs in the mid-early stage were down-regulated, and more portions of DEAPs in the mid-late and late stages were up-regulated. Approximately 22.1% (328/1,485) of acetylated peptides mapped to 74 different proteins were mitochondrial associated. Kyoto Encyclopedia of Genes and Genomes pathway analysis identified 39 (80 dpi), 13 (120 dpi), and 10 (180 dpi) significantly changed pathways in 139A-infected mice. Meanwhile, 55, 25, and 18 significantly changed pathways were observed in the 80, 120, and 180 dpi samples of 139A- and ME7-infected mice ( P < 0.05), respectively. Six pathways were commonly involved in all tested samples. Moreover, many steps in the citrate cycle (tricarboxylic acid cycle) were affected, represented by down-regulated acetylation for relevant enzymes in the mid-early stage and up-regulated acetylation in the mid-late and late stages. CONCLUSION Our data here illustrated the changes in the global profiles for brain acetylated proteins during prion infection, showing remarkably inhibited acetylation in the early stage and relatively enhanced acetylation in the late stage.
Animals ; Brain/metabolism* ; Citrates/metabolism* ; Mice ; Peptides/metabolism* ; PrPSc Proteins ; Proteomics ; Scrapie/metabolism* ; Sheep

It is very difficult to diagnosis osteoarthritis in the early stage, due to the slow development of the disease, no symptoms occures, and no X-ray findings in the early stage, it is difficult to early diagnosis with the traditional diagnostic methods, resulting in the poor treatment outcome, and even some patients develop joint deformity, activity limitation, and must take an operation, it brought great pain and heavy financial burden to patients. How to early diagnosis of articular cartilage injury become difficult now. Some scholars suggest that to those suspected patients, the arthroscopic diagnosis must be taken. Although the small trauma and quick recover, the method of operation has trauma, not only increase the suffering of the patients, but the treatment is very expensive, make the patients finch. A large number of domestic and foreign scholars to study patients with OA to find the ideal fluid biological markers (BM) to reflect articular cartilage metabolism, and revealed disease activity or prognosis. The CTX-II can reflect degradation of the articular cartilage.
Biomarkers ; metabolism ; Collagen Type I ; metabolism ; Humans ; Osteoarthritis ; diagnosis ; metabolism ; Peptides ; metabolism

Tyrosine-decahydrofluorene derivatives are a class of hybrid compounds that integrate the properties of polyketides and nonribosomal peptides. These compounds feature a [6.5.6] tricarbocyclic core and a para-cyclophane ether moiety in their structures and exhibit anti-tumor and anti-microbial activities. In this study, we constructed the biosynthetic pathway of xenoacremones from Xenoacremonium sinensis ML-31 in the Aspergillus nidulans host, resulting in the identification of four novel tyrosine-decahydrofluorene analogs, xenoacremones I-L (1-4), along with two known analogs, xenoacremones A and B. Remarkably, compounds 3 and 4 contained a 12-membered para-cyclophane ring system, which is unprecedented among tyrosine-decahydrofluorene analogs in X. sinensis. The successful reconstruction of the biosynthetic pathway and the discovery of novel analogs demonstrate the utility of heterologous expression strategy for the generation of structurally diverse natural products with potential biological activities.
Aspergillus nidulans/metabolism* ; Biological Products/metabolism* ; Polyketides/metabolism* ; Peptides/metabolism* ; Biosynthetic Pathways ; Multigene Family

Bioactive peptides play important roles in promoting human health, such as lowering blood pressure, blood sugar and blood lipid, anti-obesity, and anti-cancer. Thus, exploring functional bioactive peptides and developing efficient production technologies are of crucial importance. Herein, we review the development of function discovery and production technology for natural bioactive peptides. Presently, the top-down and bottom-up approaches are mainly used for the function discovery and production of natural active peptides. The top-down approach includes the direct extraction and identification for functional discovery, and the direct extraction, enzymatic hydrolysis and microbial fermentation for production. The bottom-up approach includes the polypeptide modification and database mining for functional discovery, and the chemical synthesis, enzyme synthesis, recombinant expression and cell-free synthesis for production. The top-down approach is usually associated with complicated process, lower efficiency, higher cost, harder quality control, and uncertain functionality, while the bottom-up approach is more suitable for the development of peptide drugs but difficult to be used for functional foods. With the technology development of sequencing and mass spectrometry, it is easier to obtain the proteomic information of various organisms at the molecular level. Based on the proteomic information, the top-down and bottom-up approaches can be combined to overcome the disadvantages of using these two approaches alone, thus providing a new strategy for the rapid development and production of natural active peptides.
Fermentation ; Humans ; Mass Spectrometry ; Peptides/metabolism* ; Proteomics ; Technology

Traumatic brain injury (TBI) is the leading cause of mortality and disability among young individuals in our society, and globally the incidence of TBI is rising sharply. Mounting evidence has indicated that apolipoprotein E (apoE: protein; APOE: gene) genotype influences the outcome after TBI. The proposed mechanism by which APOE affects the clinicopathological consequences of TBI is multifactorial and includes amyloid deposition, disruption of lipid distribution, dysfunction of mitochondrial energy production, oxidative stress and increases intracellular calcium in response to injury. This paper reviews the current state of knowledge regarding the influence of apoE and its receptors on cerebral amyloid beta-protein precursor metabolism following TBI.
Amyloid beta-Peptides ; Apolipoproteins E ; Brain Injuries ; metabolism ; Humans

Cell-penetrating peptides (CPPs) are short peptides that can penetrate the cell membrane or tissue barrier. CPPs can deliver a variety of biomacromolecules, such as proteins, RNA and DNA, into cells to produce intracellular functional effects. Endocytosis and direct penetration have been suggested as the two major uptake mechanisms for CPPs-mediated cargo delivery. Compared with other non-natural chemical molecules-based delivery reagents, the CPPs have better biocompatibility, lower cytotoxicity, are easily degraded after cargo delivery, and can be fused and recombined expressed with bioactive proteins. Because of these advantages, the CPPs have become an important potential tool for delivery of developing drugs which targets intracellular factors. As a novel delivery tool, the CPPs also show promising application prospects in biomedical researches. This review summarized recent advances regarding the classification characteristics, the cellular uptake mechanisms and therapeutic application potentials of CPPs.
Biological Transport ; Cell Membrane ; Cell-Penetrating Peptides ; metabolism ; Endocytosis

Peptide cyclization, a pivotal approach to modifying linear precursors of proteins and pepticles, has been used to enhance their biological activities and serum stabilities. Recently, sortase A (SrtA) from Staphyloccus aureus becomes a promising new technology for efficiently incorporating site specific modifications into proteins, conjugating the cell surface and cyclizing the linear peptides. In this study, we constructed two recombinant expression systems, one with chitin binding domain and the other with six-histidine tag and chitin binding domain on the N-terminal of SrtA, separately. The results of enzymatic kinetics indicate that the two recombinant tags do not impair the transpeptidase activity of SrtA compared with the standard reaction reported under the same reaction condition. The two synthesized peptides with N-ternimal three glycines and C-terminal penta-amino acid motif, LPETG, were cyclized using immobilized and recycled SrtA. The SrtA-based cyclization promises to represent a simple method for easy and efficient enzymatic synthesis of large cyclic peptides.
Aminoacyltransferases ; metabolism ; Bacterial Proteins ; metabolism ; Cyclization ; Cysteine Endopeptidases ; metabolism ; Enzymes, Immobilized ; metabolism ; Kinetics ; Peptides ; metabolism ; Peptides, Cyclic ; biosynthesis ; Staphylococcus aureus ; enzymology

Natriuretic peptides (NPs) have been found to be useful markers in differentiating acute dyspneic patients presenting to the emergency department (ED) and emerged as potent prognostic markers for patients with congestive heart failure (CHF). The best-established and widely used clinical application of BNP and NT-proBNP testing is for the emergent diagnosis of CHF in patients presenting with acute dyspnea. Nevertheless, elevated NPs levels can be found in many circumstances involving left ventricular (LV) dysfunction or hypertrophy; right ventricular (RV) dysfunction secondary to pulmonary diseases; cardiac inflammatory or infectious diseases; endocrinology diseases and high output status without decreased LV ejection fraction. Even in the absence of significant clinical evidence of volume overload or LV dysfunction, markedly elevated NP levels can be found in patients with multiple comorbidities with a certain degree of prognostic value. Potential clinical applications of NPs are expanded accompanied by emerging reports regarding screening the presence of secondary cardiac dysfunction; monitoring the therapeutic responses, risk stratifications and providing prognostic values in many settings. Clinicians need to have expanded knowledge regarding the interpretation of elevated NPs levels and potential clinical applications of NPs. Clinicians should recognize that currently the only reasonable application for routine practice is limited to differentiation of acute dyspnea, rule-out-diagnostic-tests, monitoring of therapeutic responses and prognosis of acute or decompensated CHF. The rationales as well the potential applications of NPs in these settings are discussed in this review article.
Acute Coronary Syndrome/metabolism ; Arrhythmias, Cardiac/metabolism ; Heart Failure/*metabolism ; Humans ; Hypertension, Pulmonary/metabolism ; Natriuretic Peptides/*metabolism ; Sepsis/metabolism