Fast Photochemical Oxidation of Proteins (FPOP) Maps the Epitope of EGFR Binding to Adnectin

Epitope mapping is an important tool for the development of monoclonal antibodies, mAbs, as therapeutic drugs. Recently, a class of therapeutic mAb alternatives, adnectins, has been developed as targeted biologics. They are derived from the 10th type III domain of human fibronectin (¹⁰Fn3). A common approach to map the epitope binding of these therapeutic proteins to their binding partners is X-ray crystallography. Although the crystal structure is known for Adnectin 1 binding to human epidermal growth factor receptor (EGFR), we seek to determine complementary binding in solution and to test the efficacy of footprinting for this purpose. As a relatively new tool in structural biology and complementary to X-ray crystallography, protein footprinting coupled with mass spectrometry is promising for protein–protein interaction studies. We report here the use of fast photochemical oxidation of proteins (FPOP) coupled with MS to map the epitope of EGFR-Adnectin 1 at both the peptide and amino-acid residue levels. The data correlate well with the previously determined epitopes from the crystal structure and are consistent with HDX MS data, which are presented in an accompanying paper. The FPOP-determined binding interface involves various amino-acid and peptide regions near the N terminus of EGFR. The outcome adds credibility to oxidative labeling by FPOP for epitope mapping and motivates more applications in the therapeutic protein area as a stand-alone method or in conjunction with X-ray crystallography, NMR, site-directed mutagenesis, and other orthogonal methods. Figure

?     

Two States Are Not Enough: Quantitative Evaluation of the Valence‐Bond Intramolecular Charge‐Transfer Model and Its Use in Predicting Bond Length Alternation Effects

The structural weights of the canonical resonance contributors used in the Two‐state valence‐bond charge‐transfer model, neutral (N, R1) and ionic (VB‐CT, R2), to the ground states and excited states of a series of linear dipolar intramolecular charge‐transfer chromophores containing a buta‐1,3‐dien‐1,4‐diyl bridge have been computed by using the block‐localized wavefunction (BLW) method at the B3LYP/6‐311+G(d) level to provide the first quantitative assessment of this simple model. Ground‐ and excited‐state analysis reveals surprisingly low ground‐state structural weights for the VB‐CT resonance form using either this Two‐state model or an expanded Ten‐state model. The VB‐CT state is found to be more prominent in the excited state. Individual resonance forms were structurally optimized to understand the origins of the bond length alternation (BLA) of the bridging unit. Using a Wheland energy‐based weighting scheme, the weighted average of the optimized bond lengths with the Two‐state model was unable to reproduce the BLA features with values 0.04 to 0.02 Å too large compared to the fully delocalized (FD) structure (BLW: ca. ?0.13 to ?0.07 Å, FD: ca. ?0.09 to ?0.05 Å). Instead, an expanded Ten‐state model fit the BLA values of the FD structure to within only 0.001 Å of FD.     

纳米激光粒度仪在生物药品团聚物测试中的应用

探讨了纳米激光粒度仪测定生物药品团聚物质量浓度的方法。以SALD–7500nano颗粒测试仪为例,介绍其在测量纳米级颗粒物粒度范围方面的应用。通过进一步分析颗粒浓度与光强度成正比的关系获得以质量浓度形式给出的粒度分布数据。通过牛血清蛋白(BSA)团聚物测量的实例,验证了颗粒物质量浓度的测试方法。该方法可用于生物制药领域对团聚物的监控测量以及评价药品药效、安全性能等。     

Enhanced Anticancer Efficacy by ATP‐Mediated Liposomal Drug Delivery

A liposome‐based co‐delivery system composed of a fusogenic liposome encapsulating ATP‐responsive elements with chemotherapeutics and a liposome containing ATP was developed for ATP‐mediated drug release triggered by liposomal fusion. The fusogenic liposome had a protein–DNA complex core containing an ATP‐responsive DNA scaffold with doxorubicin (DOX) and could release DOX through a conformational change from the duplex to the aptamer/ATP complex in the presence of ATP. A cell‐penetrating peptide‐modified fusogenic liposomal membrane was coated on the core, which had an acid‐triggered fusogenic potential with the ATP‐loaded liposomes or endosomes/lysosomes. Directly delivering extrinsic liposomal ATP promoted the drug release from the fusogenic liposome in the acidic intracellular compartments upon a pH‐sensitive membrane fusion and anticancer efficacy was enhanced both in vitro and in vivo.     

无碱条件下Au/ZnO选择性催化氧化1,3-丙二醇合成3-羟基丙酸甲酯

采用溶胶-沉积法合成了高选择性的Au/ZnO催化剂,用于1,3-丙二醇选择性氧化酯化为3-羟基丙酸甲酯的反应.研究了保护剂PVA用量、金溶胶合成温度、金负载量及催化剂循环利用对反应的影响,且优化了反应温度和反应压力,并对催化剂进行了XRD和TEM表征.结果表明,PVA∶Au(m/m)=1∶4、金溶胶合成温度25℃、金负载量1%的Au/ZnO对目标反应的催化活性最好,在100℃和Po2=2MPa的条件下1,3-丙二醇的转化率达82.8%,产物3-羟基丙酸甲酯的选择性达95.4%.Au纳米粒子的粒径影响催化性能,在Au平均粒径为2.8~6.1nm的范围内,产物选择性随Au纳米粒子的粒径的减小而增大,平均粒径在2.8~4.8nm的范围内时,催化剂具有较好的产物选择性(大于90%);Au/ZnO催化剂循环利用4次后催化性能(转化率和选择性)无明显下降;并推测了无碱条件下Au/ZnO选择性催化氧化1,3-丙二醇合成3-羟基丙酸甲酯的反应机制.     

Copper-Catalyzed Enantioselective Sonogashira Type Coupling of Alkynes with α-Bromoamides

An asymmetric copper-catalyzed Sonogashira type coupling between alkynes and α-bromoamides has been developed. This method represents a facile approach to synthetically useful β, γ-alkynyl amides from two readily available starting materials in a highly enantioselective manner. A Bisoxazoline diphenylanaline (BOPA) serves as the effective chiral ligand. Preliminary mechanistic studies support the formation of alkyl radical species .     

The electronic band structure analysis of OLED device by means of in situ LEIPS and UPS combined with GCIB

Low-energy inverse photoelectron spectroscopy (LEIPS) and ultraviolet photoelectron spectroscopy (UPS) incorporated into the multitechnique XPS system were used to probe the ionization potential and the electron affinity of organic materials, respectively. By utilizing gas cluster ion beam (GCIB), in situ analyses and depth profiling of LEIPS and UPS were also demonstrated. The band structures of the 10-nm-thick buckminsterfullerene (C₆₀) thin film on Au (100 nm)/indium tin oxide (100 nm)/glass substrate were successfully evaluated in depth direction.     

A modified quick,easy, cheap,effective, rugged,and safe method with hydrophobic natural deep eutectic solvent as extractant and analyte protectant for analyzing pyrethroid residues in tomatoes

In this work, a novel quick, easy, cheap, effective, rugged, and safe technique with hydrophobic natural deep eutectic solvent as both extractant and analyte protectant was developed and combined with gas chromatography–tandem mass spectrometry to analyze pyrethroid residues in tomatoes. Eight hydrophobic natural deep eutectic solvents were first evaluated as analyte protectants and those with decanoic acid or lactic acid as hydrogen bond donor were demonstrated to be effective in compensating for the matrix effects of pyrethroids in the gas chromatography system. Hence, they were added to solvent standards for correcting the quantitation errors instead of matrix‐matched calibration standards. Then the abilities of these acid‐based deep eutectic solvents to extract pyrethriods from tomatoes were evaluated. Results showed the recoveries of all pyrethroids reached to over 80% with only 5 mL menthol:decanoic acid (1:1) used, and good phase separation was easily achieved without the addition of inorganic salt in the extraction step, indicating hydrophobic natural deep eutectic solvent could be a green substitute for acetonitrile in the quick, easy, cheap, effective, rugged, and safe extraction. Compared with the conventional method, the proposed protocol improved the recoveries, reduced the matrix effects, and simplified the extraction step, demonstrating to be an effective, fast, and green method.     

Polymer Transformers: Interdigitating Reaction Networks of Fueled Monomer Species to Reconfigure Functional Polymer States

Adaptivity is an essential trait of life. One type of adaptivity is the reconfiguration of a functional system states by correlating sensory inputs. We report polymer transformers, which can adaptively reconfigure their composition from a state of a mixed copolymer to being enriched in either monomer A or B. This is achieved by embedding and hierarchically interconnecting two chemically fueled activation/deactivation enzymatic reaction networks for both monomers via a joint activation pathway (network level) and an AB linker monomer reactive to both A and B (species level). The ratio of enzymes governing the individual deactivation pathways (our external signals) control the enrichment behavior in the dynamic state. The method shows high programmability of the reconfigured state, rejuvenation of transformation cycles, and quick in situ adaptation. As a proof‐of‐concept, we showcase this dynamic reconfiguration for colloidal surface functionalities.