共查询到20条相似文献,搜索用时 31 毫秒
1.
Dr. Punit Upadhyaya Dr. Ziqing Qian Dr. Nicholas G. Selner Sarah R. Clippinger Prof. Dr. Zhengrong Wu Dr. Roger Briesewitz Prof. Dr. Dehua Pei 《Angewandte Chemie (International ed. in English)》2015,54(26):7602-7606
Ras genes are frequently activated in human cancers, but the mutant Ras proteins remain largely “undruggable” through the conventional small‐molecule approach owing to the absence of any obvious binding pockets on their surfaces. By screening a combinatorial peptide library, followed by structure–activity relationship (SAR) analysis, we discovered a family of cyclic peptides possessing both Ras‐binding and cell‐penetrating properties. These cell‐permeable cyclic peptides inhibit Ras signaling by binding to Ras‐GTP and blocking its interaction with downstream proteins and they induce apoptosis of cancer cells. Our results demonstrate the feasibility of developing cyclic peptides for the inhibition of intracellular protein–protein interactions and of direct Ras inhibitors as a novel class of anticancer agents. 相似文献
2.
Matrix‐assisted laser desorption/ionization in‐source decay (MALDI‐ISD) has been used for characterization of a phosphorylated peptides and proteins because labile phosphate group is not lost during the MALDI‐ISD process. The conventional MALDI‐ISD is initiated by the hydrogen transfer from reducing matrix molecules to peptide backbone, leading to c′‐ and z′‐series ions. In contrast, when an oxidizing chemical 5‐nitrosalicylic acid (5‐NSA) is served as the MALDI‐ISD matrix, a‐ and x‐series ions are specifically generated by hydrogen abstraction from peptide backbone to matrix molecule. The 5‐NSA provides useful complementary information to the conventional MALDI‐ISD for the analysis of amino acid sequencing and site localization of phosphorylation in peptides. The MALDI‐ISD with reducing and oxidizing matrix could be a useful method for the de novo peptide sequencing. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
3.
Present proteomics and biomedicine require sensitive analytical methods for all proteins. Recent progress in electrochemical analysis of peptides and proteins based on their intrinsic electroactivity is reviewed. Tyrosine and/or tryptophan‐containing proteins are oxidizable at carbon electrodes. At mercury electrodes all peptides and proteins (about 13 peptides and >25 proteins were tested) produce chronopotentiometric peak H at nanomolar concentrations. This peak is sensitive to changes in protein structure. Microliter sample volumes are sufficient for the analysis. Electrochemical methods can be used in studies of nucleic acid‐protein interactions and can be applied in biomedicine. Examples of such applications in neurogenerative diseases and cancer are presented. 相似文献
4.
Nonproteinogenic Amino Acid Building Blocks for Nonribosomal Peptide and Hybrid Polyketide Scaffolds
Prof. Christopher T. Walsh Dr. Robert V. O'Brien Prof. Chaitan Khosla 《Angewandte Chemie (International ed. in English)》2013,52(28):7098-7124
Freestanding nonproteinogenic amino acids have long been recognized for their antimetabolite properties and tendency to be uncovered to reactive functionalities by the catalytic action of target enzymes. By installing them regiospecifically into biogenic peptides and proteins, it may be possible to usher a new era at the interface between small molecule and large molecule medicinal chemistry. Site‐selective protein functionalization offers uniquely attractive strategies for posttranslational modification of proteins. Last, but not least, many of the amino acids not selected by nature for protein incorporation offer rich architectural possibilities in the context of ribosomally derived polypeptides. This Review summarizes the biosynthetic routes to and metabolic logic for the major classes of the noncanonical amino acid building blocks that end up in both nonribosomal peptide frameworks and in hybrid nonribosomal peptide‐polyketide scaffolds. 相似文献
5.
Dr. Benjamí Oller‐Salvia Dr. Macarena Sánchez‐Navarro Sonia Ciudad Marc Guiu Pol Arranz‐Gibert Cristina Garcia Dr. Roger R. Gomis Prof. Roméo Cecchelli Dr. Jesús García Prof. Ernest Giralt Dr. Meritxell Teixidó 《Angewandte Chemie (International ed. in English)》2016,55(2):572-575
Drug delivery across the blood–brain barrier (BBB) is a formidable challenge for therapies targeting the central nervous system. Although BBB shuttle peptides enhance transport into the brain non‐invasively, their application is partly limited by lability to proteases. The present study proposes the use of cyclic peptides derived from venoms as an affordable way to circumvent this drawback. Apamin, a neurotoxin from bee venom, was minimized by reducing its complexity, toxicity, and immunogenicity, while preserving brain targeting, active transport, and protease resistance. Among the analogues designed, the monocyclic lactam‐bridged peptidomimetic MiniAp‐4 was the most permeable. This molecule is capable of translocating proteins and nanoparticles in a human‐cell‐based BBB model. Furthermore, MiniAp‐4 can efficiently deliver a cargo across the BBB into the brain parenchyma of mice. 相似文献
6.
Alexander P. Boichenko Natalia Govorukhina Ate G. J. van der Zee Rainer Bischoff 《Journal of separation science》2013,36(21-22):3463-3470
Proteome profiling of crude serum is a challenging task due to the wide dynamic range of protein concentrations and the presence of high‐abundance proteins, which cover >90% of the total protein mass in serum. Peptide fractionation on strong cation exchange, weak anion exchange in the electrostatic repulsion hydrophilic interaction chromatography (ERLIC) mode, RP C18 at pH 2.5 (low pH), fused‐core fluorinated at pH 2.5, and RP C18 at pH 9.7 (high pH) stationary phases resulted in two to three times more identified proteins and three to four times more identified peptides in comparison with 1D nanoChip‐LC–MS/MS quadrupole TOF analysis (45 proteins, 185 peptides). The largest number of peptides and proteins was identified after prefractionation in the ERLIC mode due to the more uniform distribution of peptides among the collected fractions and on the RP column at high pH due to the high efficiency of RP separations and the complementary selectivity of both techniques to low‐pH RP chromatography. A 3D separation scheme combining ERLIC, high‐pH RP, and low‐pH nanoChip‐LC–MS/MS for crude serum proteome profiling resulted in the identification of 208 proteins and 1088 peptides with the lowest reported concentration of 11 ng/mL for heat shock protein 74. 相似文献
7.
Kan Xiong Graham S. Erwin Prof. Aseem Z. Ansari Prof. Paul C. Blainey 《Angewandte Chemie (International ed. in English)》2016,55(48):15110-15114
Many DNA binding proteins utilize one‐dimensional (1D) diffusion along DNA to accelerate their DNA target recognition. Although 1D diffusion of proteins along DNA has been studied for decades, a quantitative understanding is only beginning to emerge and few chemical tools are available to apply 1D diffusion as a design principle. Recently, we discovered that peptides can bind and slide along DNA—even transporting cargo along DNA. Such molecules are known as molecular sleds. Here, to advance our understanding of structure–function relationships governing sequence nonspecific DNA interaction of natural molecular sleds and to explore the potential for controlling sliding activity, we test the DNA binding and sliding activities of chemically modified peptides and analogs, and show that synthetic small molecules can slide on DNA. We found new ways to control molecular sled activity, novel small‐molecule synthetic sleds, and molecular sled activity in N‐methylpyrrole/N‐methylimidazole polyamides that helps explain how these molecules locate rare target sites. 相似文献
8.
We utilized three different types of TiO2 nanoparticles (NPs) namely TiO2‐dopamine, TiO2‐CdS and bare TiO2 NPs as multifunctional nanoprobes for the rapid enrichment of phosphopeptides from tryptic digests of α‐ and β‐casein, milk and egg white using a simplified procedure in MALDI‐TOF‐MS. Surface‐modified TiO2 NPs serve as effective matrices for the analysis of peptides (gramicidin D, HW6, leucine‐enkephalin and methionine‐enkephalin) and proteins (cytochrome c and myoglobin) in MALDI‐TOF‐MS. In the surface‐modified TiO2 NPs‐based MALDI mass spectra of these analytes (phosphopetides, peptides and proteins), we found that TiO2‐dopamine and bare TiO2 NPs provided an efficient platform for the selective and rapid enrichment of phosphopeptides and TiO2‐CdS NPs efficiently acted as the matrix for background‐free detection of peptides and proteins with improved resolution in MALDI‐MS. We found that the upper detectable mass range is 17 000 Da using TiO2‐CdS NPs as the matrix. The approach is simple and straightforward for the rapid analysis of phosphopeptides, peptides and proteins by MALDI‐MS in proteome research. 相似文献
9.
Rajkumar Misra Gijo George Abhijith Saseendran Srinivasarao Raghothama Hosahudya N. Gopi 《化学:亚洲杂志》2019,14(23):4408-4414
Molecular chirality is ubiquitous in nature. The natural biopolymers, proteins and DNA, preferred a right‐handed helical bias due to the inherent stereochemistry of the monomer building blocks. Here, we are reporting a rare co‐existence of left‐ and right‐handed helical conformations and helix‐terminating property at the C‐terminus within a single molecule of α,γ‐hybrid peptide foldamers composed of achiral Aib (α‐aminoisobutyric acid) and 3,3‐dimethyl‐substituted γ‐amino acid (Adb; 4‐amino‐3,3‐dimethylbutanoic acid). At the molecular level, the left‐ and right‐handed helical screw sense of α,γ‐hybrid peptides are representing a macroscopic tendril perversion. The pronounced helix‐terminating behaviour of C‐terminal Adb residues was further explored to design helix–Schellman loop mimetics and to study their conformations in solution and single crystals. The stereochemical constraints of dialkyl substitutions on γ‐amino acids showed a marked impact on the folding behaviour of α,γ‐hybrid peptides. 相似文献
10.
Bao‐Shiang Lee Sangeeth Krishnanchettiar Syed Salman Lateef Shalini Gupta 《中国化学会会志》2007,54(2):541-548
Biocytin hydrazide is widely used to biotinylate the carbohydrate moieties of glycoproteins. In this study, however, biocytin hydrazide was found to be able to directly biotinylate peptides and proteins. This phenomenon may cause false identification of non‐glycopeptides/non‐glycoproteins as glycopeptides/glycoproteins. Here, we report a systematic investigation of the reaction of peptides/proteins with biocytin hydrazide. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry is used to analyze the biotinylation reaction between peptides/proteins and biocytin hydrazide. Peptides/proteins were reacted with biocytin hydrazide in diverse solvent systems with different biocytin hydrazide concentrations for up to 96 h at temperatures ranging from 4 °C to 65 °C. Singly biotinylated or multiply biotinylated peptides/proteins are observed. The efficiency of the biotinylation reaction increases with higher temperature, higher biocytin hydrazide concentration, or longer reaction time. The influence of buffer pH on the biotinylation reaction of peptides/proteins is less pronounced. The biotinylation efficiency is optimum at neutral pH. Data suggests that the peptides are biotinylated as efficiently as proteins. The observation that peptides/proteins condense only with biocytin hydrazide, 2‐iminobiotin hydrazide, adipic dihydrazide and phenyl hydrazine but not with biocytin HCl and 2‐iminobiotin, indicates that the biotinylation reaction of peptides/proteins occurs with the hydrazide moiety but not with biotin moiety of the biotinylated reagent. The postsource decay data of biotinylated P14R indicates that biocytin hydrazide condenses with the guanidino group of arginine's side chain of P14R, indicating that besides N‐terminal and lysine residue of peptides/proteins, arginine residue is capable of reacting with biocytin hydrazide. 相似文献
11.
《Journal of mass spectrometry : JMS》2017,52(2):127-131
The ability of a thiol‐containing molecule, thiosalicylic acid (TSA), to function as a reactive matrix for matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry analysis of peptides has been investigated. Although TSA has reducing characteristics, the use of TSA did not cause a reduction‐induced MALDI in‐source decay, probably because of the weak interactions between the thiol group in TSA and the carboxyl oxygen in the peptide. In contrast, when peptides containing disulfide bonds were analyzed by MALDI with TSA as the matrix, the disulfide bond was partially cleaved owing to the reaction with TSA, producing TSA‐adducted peptides. The reaction between the disulfide bond and TSA was suggested to be occurred in solution. The comparison of the MALDI mass spectra obtained using conventional matrix and TSA allows us to count the number of disulfide bonds in the peptides. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
12.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(16):4529-4534
We report the discovery of a small phenyl molecule with four isosteric thiolate‐reactive groups of sequentially varied reactivity. This molecule was exploited in combination with cysteine/penicillamine thiolates of different nucleophilic reactivity for precisely regulated and efficient locking (PROP‐locking) of linear peptides into multicyclic topologies through a one‐pot reaction. The PROP‐locking relies on multistep and sequential thiolate/fluorine nucleophilic substitutions, which is not only rapid but highly specific, thus enabling rapid locking of peptides with high amino acid diversities without protecting groups. Several tricyclic peptide templates and bioactive peptides were designed and synthesized using the PROP‐locking strategy. We believe that tricyclic peptides precisely locked through stable thioether bonds should be promising structurally constrained scaffolds for developing potential therapeutics and target ligands. 相似文献
13.
Dr. Kai Xiao Kai Wu Lu Chen Dr. Xiang‐Yu Kong Prof. Yuqi Zhang Prof. Liping Wen Prof. Lei Jiang 《Angewandte Chemie (International ed. in English)》2018,57(1):151-155
The controllable molecule transport is crucial to realize many highly valuable applications both in vivo and in vitro. Nanoporous membranes, with nanoscopic pores, high porosity, uniform pore dimensions, and controllable surface chemical properties, hold tremendous potential to achieve this function. Herein, we report a nano‐gating system for on‐demand molecule transport based on a peptide‐gated nanoporous membrane. Acting as gatekeeper, the peptides introduced to the nanoporous membrane provide an opportunity to realize on‐demand on–off states via reversible conformational switching of the peptides. This nano‐gating system offers sustained release and can be used as a sophisticated molecule transport platform for localized drug delivery with a feedback function. 相似文献
14.
《Angewandte Chemie (International ed. in English)》2017,56(49):15755-15759
Calmodulin (CaM) binds most of its targets by wrapping around an amphipathic α‐helix. The N‐terminus of Orai proteins contains a conserved CaM‐binding segment but the binding mechanism has been only partially characterized. Here, microscale thermophoresis (MST), surface plasmon resonance (SPR), and atomic force microscopy (AFM) were employed to study the binding equilibria, the kinetics, and the single‐molecule interaction forces involved in the binding of CaM to the conserved helical segments of Orai1 and Orai3. The results consistently indicated stepwise binding of two separate target peptides to the two lobes of CaM. An unparalleled high affinity was found when two Orai peptides were dimerized or immobilized at high lateral density, thereby mimicking the close proximity of the N‐termini in native Orai oligomers. The analogous experiments with smooth muscle myosin light chain kinase (smMLCK) showed only the expected 1:1 binding, confirming the validity of our methods. 相似文献
15.
Ralph Wieneke Robert Tamp 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(25):8364-8376
With the advent of single‐molecule methods, chemoselective and site‐specific labeling of proteins evolved to become a central aspect in chemical biology as well as cell biology. Protein labeling demands high specificity, rapid as well as efficient conjugation, while maintaining low concentration and biocompatibility under physiological conditions. Generic methods that do not interfere with the function, dynamics, subcellular localization of proteins, and crosstalk with other factors are crucial to probe and image proteins in vitro and in living cells. Alternatives to enzyme‐based tags or autofluorescent proteins are short peptide‐based recognition tags. These tags provide high specificity, enhanced binding rates, bioorthogonality, and versatility. Here, we report on recent applications of multivalent chelator heads, recognizing oligohistidine‐tagged proteins. The striking features of this system has facilitated the analysis of protein complexes by single‐molecule approaches. 相似文献
16.
Schober Y Schramm T Spengler B Römpp A 《Rapid communications in mass spectrometry : RCM》2011,25(17):2475-2483
The spatial distribution of proteins in tissue sections can be used to identify potential markers for pathological processes. Tissue sections are often subjected to enzymatic digestion before matrix‐assisted laser desorption/ionization (MALDI) imaging. This study is targeted at improving the on‐tissue identification of tryptic peptides by accurate mass measurements and complementary off‐line liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC/ESI‐MS/MS) analysis. Two adjacent mouse brain sections were analyzed in parallel. The first section was spotted with trypsin and analyzed by MALDI imaging. Direct on‐tissue MS/MS experiments of this section resulted in the identification of 14 peptides (originating from 4 proteins). The second tissue section was homogenized, fractionated by ultracentrifugation and digested with trypsin prior to LC/ESI‐MS/MS analysis. The number of identified peptides was increased to 153 (corresponding to 106 proteins) by matching imaged mass peaks to peptides which were identified in these LC/ESI‐MS/MS experiments. All results (including MALDI imaging data) were based on accurate mass measurements (RMS <2 ppm) and allow a confident identification of tryptic peptides. Measurements based on lower accuracy would have led to ambiguous or misleading results. MS images of identified peptides were generated with a bin width (mass range used for image generation) of Δm/z = 0.01. The application of accurate mass measurements and additional LC/MS measurements increased both the quality and the number of peptide identifications. The advantages of this approach for the analysis of biological tissue sections are demonstrated and discussed in detail. Results indicate that accurate mass measurements are needed for confident identification and specific image generation of tryptic peptides in tissue sections. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
17.
《Electrophoresis》2017,38(3-4):401-407
Four methods were compared for analysis of host‐cell protein (HCP) impurities in a recombinant mAb. First, CZE‐MS/MS was used to analyze the digest of an HCP sample following extraction of the mAb with proteins A and L affinity columns; 220 protein groups and 976 peptides were identified from the depleted HCP digest. Second, a nanoACQUITY UltraPerformance LCH system was also used to analyze the depleted HCP digest; 34 protein groups and 53 peptides from 50 ng of the depleted HCP digest and 290 protein groups and 1011 peptides were identified from 1 μg of the depleted HCP digest. Third, 185 protein groups and 709 peptides were identified by CZE‐MS/MS from the HCP digest without depletion. Fourth, a strong cation exchange SPE was coupled to CZE‐ESI‐MS/MS using online pH gradient elution for analysis of the HCP digest without depletion. A series of five pH bumps were applied to elute peptides from the strong cation exchange monolith followed by analysis using CZE coupled to a Q Exactive HF mass spectrometer; 230 protein groups and 796 peptides were identified from the HCP digest without depletion. 相似文献
18.
Recently,thestudiesofX-rayandmolecularbiologyontheinteractionofproteinssuchasantigen-antibody,hormone-receptorandsoonshowthatonlyasmallportionoftheproteinmo1eculetakespartintheinteractionotherthanthewholemolecule,andshortpeptidesbearingcriticalbindingresiduescanbeusedtochemicallymimicthefoldedantigenicdeterminantsonproteins['1.Wede-signedandsynthesizedamodelpeptidemimickingtheactivesiteoftrypsin(apeptide,DGGSAA)basedonthethree-dimensionalstructureoftrypsinanditscatalyticmechanism[2J,andusedt… 相似文献
19.
Shiyu Chen Davide Bertoldo Alessandro Angelini Florence Pojer Christian Heinis 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(6):1628-1632
Bicyclic peptides generated through directed evolution by using phage display offer an attractive ligand format for the development of therapeutics. Being nearly 100‐fold smaller than antibodies, they promise advantages such as access to chemical synthesis, efficient diffusion into tissues, and needle‐free application. However, unlike antibodies, they do not have a folded structure in solution and thus bind less well. We developed bicyclic peptides with hydrophilic chemical structures at their center to promote noncovalent intramolecular interactions, thereby stabilizing the peptide conformation. The sequences of the peptides isolated by phage display from large combinatorial libraries were strongly influenced by the type of small molecule used in the screen, thus suggesting that the peptides fold around the small molecules. X‐ray structure analysis revealed that the small molecules indeed formed hydrogen bonds with the peptides. These noncovalent interactions stabilize the peptide–protein complexes and contribute to the high binding affinity. 相似文献
20.
Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is a rapid and sensitive analytical method that
is well suited for determining molecular weights of peptides and proteins from complex samples. MALDI-MS can be used to profile
the peptides and proteins from single-cell and small tissue samples without the need for extensive sample preparation. Furthermore,
the recently developed MALDI imaging technique enables mapping of the spatial distribution of signaling molecules in tissue
samples. Several examples of signaling molecule analysis at the single-cell and single-organ levels using MALDI-MS technology
are highlighted followed by an outlook of future directions. 相似文献