scholarly journals Chemically Crosslinked Bispecific Antibodies for Cancer Therapy: Breaking from the Structural Restrictions of the Genetic Fusion Approach

2020 ◽  
Vol 21 (3) ◽  
pp. 711
Author(s):  
Asami Ueda ◽  
Mitsuo Umetsu ◽  
Takeshi Nakanishi ◽  
Kentaro Hashikami ◽  
Hikaru Nakazawa ◽  
...  
Keyword(s):  
Chimeric Protein ◽  
Building Blocks ◽  
Genetic Mutation ◽  
Bispecific Antibodies ◽  
Specific Chemical ◽  
Module Design ◽  
Chemical Conjugation ◽  
Lysine Residues ◽  
Genetic Fusion ◽  
And Function

Antibodies are composed of structurally and functionally independent domains that can be used as building blocks to construct different types of chimeric protein-format molecules. However, the generally used genetic fusion and chemical approaches restrict the types of structures that can be formed and do not give an ideal degree of homogeneity. In this study, we combined mutation techniques with chemical conjugation to construct a variety of homogeneous bivalent and bispecific antibodies. First, building modules without lysine residues—which can be chemical conjugation sites—were generated by means of genetic mutation. Specific mutated residues in the lysine-free modules were then re-mutated to lysine residues. Chemical conjugation at the recovered lysine sites enabled the construction of homogeneous bivalent and bispecific antibodies from block modules that could not have been so arranged by genetic fusion approaches. Molecular evolution and bioinformatics techniques assisted in finding viable alternatives to the lysine residues that did not deactivate the block modules. Multiple candidates for re-mutation positions offer a wide variety of possible steric arrangements of block modules, and appropriate linkages between block modules can generate highly bioactive bispecific antibodies. Here, we propose the effectiveness of the lysine-free block module design for site-specific chemical conjugation to form a variety of types of homogeneous chimeric protein-format molecule with a finely tuned structure and function.

scholarly journals Bioelectrocatalytic hydrogels from electron-conducting metallopolypeptides coassembled with bifunctional enzymatic building blocks

2008 ◽  
Vol 105 (40) ◽  
pp. 15275-15280 ◽  
Author(s):  
Ian R. Wheeldon ◽  
Joshua W. Gallaway ◽  
Scott Calabrese Barton ◽  
Scott Banta
Keyword(s):  
Polyphenol Oxidase ◽  
Building Block ◽  
Leucine Zipper ◽  
Electrical Contact ◽  
Building Blocks ◽  
Coiled Coils ◽  
Biofuel Cell ◽  
Random Coil ◽  
Catalytic Current ◽  
And Function

Here, we present two bifunctional protein building blocks that coassemble to form a bioelectrocatalytic hydrogel that catalyzes the reduction of dioxygen to water. One building block, a metallopolypeptide based on a previously designed triblock polypeptide, is electron-conducting. A second building block is a chimera of artificial α-helical leucine zipper and random coil domains fused to a polyphenol oxidase, small laccase (SLAC). The metallopolypeptide has a helix–random-helix secondary structure and forms a hydrogel via tetrameric coiled coils. The helical and random domains are identical to those fused to the polyphenol oxidase. Electron-conducting functionality is derived from the divalent attachment of an osmium bis-bipyrdine complex to histidine residues within the peptide. Attachment of the osmium moiety is demonstrated by mass spectroscopy (MS-MALDI-TOF) and cyclic voltammetry. The structure and function of the α-helical domains are confirmed by circular dichroism spectroscopy and by rheological measurements. The metallopolypeptide shows the ability to make electrical contact to a solid-state electrode and to the redox centers of modified SLAC. Neat samples of the modified SLAC form hydrogels, indicating that the fused α-helical domain functions as a physical cross-linker. The fusion does not disrupt dimer formation, a necessity for catalytic activity. Mixtures of the two building blocks coassemble to form a continuous supramolecular hydrogel that, when polarized, generates a catalytic current in the presence of oxygen. The specific application of the system is a biofuel cell cathode, but this protein-engineering approach to advanced functional hydrogel design is general and broadly applicable to biocatalytic, biosensing, and tissue-engineering applications.

Studies on the structure and function of 16S ribosomal RNA using structure-specific chemical probes

1985 ◽  
Vol 8 (3-4) ◽  
pp. 747-755 ◽  
Author(s):  
Harry F. Noller ◽  
Barbara J. Van Stolk ◽  
Danesh Moazed ◽  
Stephen Douthwaite ◽  
Robin R. Gutell
Keyword(s):  
Ribosomal Rna ◽  
Structure And Function ◽  
16S Ribosomal Rna ◽  
Chemical Probes ◽  
Specific Chemical ◽  
And Function

A Molecular Artisans Guide to Supramolecular Coordination Complexes and Metal Organic Frameworks

2015 ◽  
Vol 03 (01n02) ◽  
pp. 1540004 ◽  
Author(s):  
Xialu Wu ◽  
David J. Young ◽  
T. S. Andy Hor
Keyword(s):  
Chemical Reactivity ◽  
Metal Organic Frameworks ◽  
Building Blocks ◽  
Coordination Complexes ◽  
Large Molecules ◽  
Molecular Building Blocks ◽  
Supramolecular Coordination ◽  
Metal Organic ◽  
Molecular Synthesis ◽  
And Function

As molecular synthesis advances, we are beginning to learn control of not only the chemical reactivity (and function) of molecules, but also of their interactions with other molecules. It is this basic idea that has led to the current explosion of supramolecular science and engineering. Parallel to this development, chemists have been actively pursuing the design of very large molecules using basic molecular building blocks. Herein, we review the general development of supramolecular chemistry and particularly of two new branches: supramolecular coordination complexes (SCCs) and metal organic frameworks (MOFs). These two fields are discussed in detail with typical examples to illustrate what is now possible and what challenges lie ahead for tomorrow's molecular artisans.

Islands of acetylated histone H4 in polytene chromosomes and their relationship to chromatin packaging and transcriptional activity

1990 ◽  
Vol 96 (2) ◽  
pp. 335-346
Author(s):  
B.M. Turner ◽  
L. Franchi ◽  
H. Wallace
Keyword(s):  
Polytene Chromosomes ◽  
Active Regions ◽  
Immunogold Electron Microscopy ◽  
Double Labelling ◽  
Histone H4 ◽  
Nucleosome Core ◽  
Amino Terminal ◽  
Experimental Systems ◽  
Lysine Residues ◽  
And Function

The four histones of the nucleosome core particle are all subject to enzyme-catalysed, post-translational acetylation at defined lysine residues in their amino-terminal domains. Much circumstantial evidence suggests a role for this process in modifying chromatin structure and function, but detailed mechanisms have not been defined. To facilitate studies on the functional significance of histone acetylation, we have prepared antibodies specific for the acetylated isoforms of histone H4. Because of the extreme evolutionary conservation of H4, these antisera can be applied to a wide variety of organisms and experimental systems. In the present study we have used polytene chromosomes from the salivary glands of larvae of the midge Chironomus to examine the distribution of acetylated H4 in interphase chromatin. By indirect immunofluorescence, antisera to acetylated H4 labeled the four Chironomus chromosomes with reproducible patterns of sharply defined, fluorescent bands. An antiserum to non-acetylated H4 gave a completely different, more-diffuse labelling pattern. Thus, there are defined regions, or islands, in the interphase genome that are enriched in acetylated H4. Double-labelling experiments with two antisera specific for H4 molecules acetylated at different sites, showed that each antiserum gave the same banding pattern. Immunolabelling patterns were not dependent on the pattern of phase-dense bands characteristic of these chromosomes; strongly labelled regions could correspond to phase-dense bands (i.e. condensed chromatin), to interbands or, frequently, to band-interband junctions. Immunogold electron microscopy confirmed the immunofluorescence results and showed further that regions of relatively high labelling could be either transcriptionally active or quiescent, as judged by the presence or absence of ribonucleoprotein particles. Two rapidly transcribed genes on chromosome 4 of Chironomus form characteristic ‘puffs’, the Balbiani rings BRb and BRc. The antiserum to non-acetylated H4 gave diffuse labelling throughout these puffs, demonstrating the continued presence of this histone in these transcriptionally active regions. Antisera to acetylated H4 strongly labelled the boundaries of BRb and BRc, and revealed clearly defined islands of increased H4 acetylation just within the expanded chromatin of the puffs. Labelling within the central region of each puff was much less intense. A similar pattern was observed in puffs on other chromosomes. Thus, increased H4 acetylation is not found throughout actively transcribed chromatin but occurs only at defined sites, possibly in the non-transcribed flanking regions. H4 acetylation is clearly not required for the passage of RNA polymerase through the nucleosome and we speculate that its role may be to facilitate the binding to DNA of polymerases and other proteins prior to the onset of transcription and possibly replication.

A Dynamic Route to Structure and Function: Recent Advances in Imine-Based Organic Nanostructured Materials

2013 ◽  
Vol 66 (1) ◽  
pp. 9 ◽  
Author(s):  
Yi Liu ◽  
Zhan-Ting Li
Keyword(s):  
Self Assembly ◽  
Reaction System ◽  
Functional Materials ◽  
Building Blocks ◽  
The Self ◽  
Interlocked Molecules ◽  
Functional Aspects ◽  
Imine Bond ◽  
And Function ◽  
Dynamic Route

The chemistry of imine bond formation from simple aldehyde and amine precursors is among the most powerful dynamic covalent chemistries employed for the construction of discrete molecular objects and extended molecular frameworks. The reversible nature of the C=N bond confers error-checking and proof-reading capabilities in the self-assembly process within a multi-component reaction system. This review highlights recent progress in the self-assembly of complex organic molecular architectures that are enabled by dynamic imine chemistry, including molecular containers with defined geometry and size, mechanically interlocked molecules, and extended frameworks and polymers, from building blocks with preprogrammed steric and electronic information. The functional aspects associated with the nanometer-scale features not only place these dynamically constructed nanostructures at the frontier of materials sciences, but also bring unprecedented opportunities for the discovery of new functional materials.

scholarly journals Large-area display textiles integrated with functional systems

2020 ◽  
Author(s):  
Huisheng Peng ◽  
Xiang Shi ◽  
Yong Zuo ◽  
Peng Zhai ◽  
Jiahao Shen ◽  
...  
Keyword(s):  
Building Blocks ◽  
Speech Disorders ◽  
Communication Tool ◽  
Electronic Textiles ◽  
Large Area ◽  
Practical Applications ◽  
Contact Points ◽  
Luminescent Coating ◽  
And Function ◽  
The Internet Of Things

Abstract Displays are basic building blocks of modern electronics1,2. Integrating displays into textiles offers exciting opportunities for smart electronic textiles – the ultimate form of wearables poised to change the way we interact with electronic devices3-6. Display textiles serve to bridge human-machine interactions7-9, offering for instance, a real-time communication tool for individuals with voice or speech disorders. Electronic textiles capable of communicating10, sensing11,12 and supplying electricity13,14 have been reported previously. However, textiles with functional, large-area displays have not been achieved so far because obtaining small illuminating units that are both durable and easy to assemble over a wide area is challenging. Here, we report a 6 m (L) * 25 cm (W) display textile containing 500000 electroluminescent (EL) units narrowly spaced to ~800 μm. Weaving conductive weft and luminescent warp fibres forms micron-scale EL units at the weft-warp contact points. Brightness between EL units deviates by < 6.3% and remains stable even when the textile is bent, stretched or pressed. We attribute this uniform and stable lighting to the smooth luminescent coating around the warp fibres and homogenous electric field distribution at the contact points. Our display textile is flexible and breathable and withstands repeatable machine-washing, making them suitable for practical applications. We show an integrated textile system consisting of display, keyboard and power supply can serve as a communication tool, which could potentially drive the Internet of Things in various areas including healthcare. Our approach unifies the fabrication and function of electronic devices with textiles, and we expect weaving fibre materials to shape the next-generation electronics.

scholarly journals Microhydration of ionized building blocks of DNA/RNA: infrared spectra of pyrimidine$$^{+}$$-$$(\hbox {H}_{2}\hbox {O})_{\text {1-3}}$$ clusters

2021 ◽  
Vol 75 (3) ◽  
Author(s):  
Kuntal Chatterjee ◽  
Otto Dopfer
Keyword(s):  
Density Functional ◽  
Size Range ◽  
Density Functional Theory Calculations ◽  
Building Blocks ◽  
Ion Solvation ◽  
Structure Stability ◽  
Consistent Picture ◽  
Three Body ◽  
And Function ◽  
Stable Structures

Abstract Hydration of biomolecules is an important physiological process that governs their structure, stability, and function. Herein, we probe the microhydration structure of cationic pyrimidine (Pym), a common building block of DNA/RNA bases, by infrared photodissociation spectroscopy (IRPD) of mass-selected microhydrated clusters, $$\hbox {Pym}^{+}$$ Pym + -$$\hbox {W}_{n}$$ W n (W=$$\hbox {H}_{2}\hbox {O}$$ H 2 O ), in the size range $$n=1$$ n = 1 –3. The IRPD spectra recorded in the OH and CH stretch range are sensitive to the evolution of the hydration network. Analysis with density functional theory calculations at the dispersion-corrected B3LYP-D3/aug-cc-pVTZ level provides a consistent picture of the most stable structures and their energetic and vibrational properties. The global minima of $$\hbox {Pym}^{+}$$ Pym + -$$\hbox {W}_{n}$$ W n predicted by the calculations are characterized by H-bonded structures, in which the H-bonded $$\hbox {W}_{n}$$ W n solvent cluster is attached to the most acidic C4–H proton of $$\hbox {Pym}^{+}$$ Pym + via a single CH...O ionic H-bond. These isomers are identified as predominant carrier of the IRPD spectra, although less stable local minima provide minor contributions. In general, the formation of the H-bonded solvent network (exterior ion solvation) is energetically preferred to less stable structures with interior ion solvation because of cooperative nonadditive three-body polarization effects. Progressive hydration activates the C4–H bond, along with increasing charge transfer from $$\hbox {Pym}^{+}$$ Pym + to $$\hbox {W}_{n}$$ W n , although no proton transfer is observed in the size range $$n\leqslant $$ n ⩽ 3. The solvation with protic, dipolar, and hydrophilic W ligands is qualitative different from solvation with aprotic, quadrupolar, and hydrophobic $$\hbox {N}_{2}$$ N 2 ligands, which strongly prefer interior ion solvation by $$\uppi $$ π stacking interactions. Comparison of $$\hbox {Pym}^{+}$$ Pym + -W with Pym-W and $$\hbox {H}^{+}$$ H + Pym-W reveals the drastic effect of ionization and protonation on the Pym...W interaction. Graphic Abstract

scholarly journals Lysosome Targeting Chimeras (LYTACs) That Engage a Liver-Specific Asialoglycoprotein Receptor for Targeted Protein Degradation

2020 ◽  
Author(s):  
Green Ahn ◽  
Steven Banik ◽  
Caitlyn L. Miller ◽  
Nicholas Riley ◽  
Jennifer R. Cochran ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Protein Degradation ◽  
Pharmacokinetic Profile ◽  
Asialoglycoprotein Receptor ◽  
Surface Proteins ◽  
New Paradigm ◽  
Specific Chemical ◽  
Chemical Conjugation ◽  
Reduce Cell Proliferation

<p>Selective protein degradation platforms have afforded new development opportunities for therapeutics and tools for biological inquiry. The first lysosome targeting chimeras (LYTACs) targeted extracellular and membrane proteins for degradation by bridging a target protein to an endogenous lysosome targeting receptor, the cation-independent mannose-6-phosphate receptor (CI-M6PR). Here we developed LYTACs that engage the asialoglycoprotein receptor (ASGPR), a liver-specific lysosomal targeting receptor, to degrade membrane proteins in a tissue-specific manner. We conjugated antibody-based binders targeting cell-surface proteins to a tri-GalNAc motif that engages ASGPR. The resulting LYTACs directed lysosome trafficking of the bound targets and subsequent degradation. Degradation mediated by an EGFR-targeted GalNAc-LYTAC resulted in significant functional effects on the downstream kinase signaling of EGFR compared to canonical inhibition with a monoclonal antibody. Furthermore, we demonstrated that a small target binder, a 3.4 kDa peptide, can be linked to a single tri-GalNAc ligand to degrade integrins and significantly reduce cell proliferation. Site-specific chemical conjugation of one or two tri-GalNAc ligands to antibody scaffolds improved the pharmacokinetic profile of GalNAc-LYTACs <i>in vivo</i> compared to non-specific chemical conjugation. GalNAc-LYTACs represent an exciting new paradigm for cell-type restricted degradation of proteins.</p>

scholarly journals Lamin B1 and lamin B2 are long-lived proteins with distinct functions in retinal development

2016 ◽  
Vol 27 (12) ◽  
pp. 1928-1937 ◽  
Author(s):  
David Razafsky ◽  
Candace Ward ◽  
Chloe Potter ◽  
Wanqiu Zhu ◽  
Yunlu Xue ◽  
...  
Keyword(s):  
Nuclear Lamina ◽  
Building Blocks ◽  
Postnatal Life ◽  
Cone Photoreceptors ◽  
Obvious Effect ◽  
Lamin B1 ◽  
Embryonic Neurogenesis ◽  
And Function ◽  
Embryonic Retina ◽  
Rod And Cone Photoreceptors

Lamin B1 and lamin B2 are essential building blocks of the nuclear lamina, a filamentous meshwork lining the nucleoplasmic side of the inner nuclear membrane. Deficiencies in lamin B1 and lamin B2 impair neurodevelopment, but distinct functions for the two proteins in the development and homeostasis of the CNS have been elusive. Here we show that embryonic depletion of lamin B1 in retinal progenitors and postmitotic neurons affects nuclear integrity, leads to the collapse of the laminB2 meshwork, impairs neuronal survival, and markedly reduces the cellularity of adult retinas. In stark contrast, a deficiency of lamin B2 in the embryonic retina has no obvious effect on lamin B1 localization or nuclear integrity in embryonic retinas, suggesting that lamin B1, but not lamin B2, is strictly required for nucleokinesis during embryonic neurogenesis. However, the absence of lamin B2 prevents proper lamination of adult retinal neurons, impairs synaptogenesis, and reduces cone photoreceptor survival. We also show that lamin B1 and lamin B2 are extremely long-lived proteins in rod and cone photoreceptors. OF interest, a complete absence of both proteins during postnatal life has little or no effect on the survival and function of cone photoreceptors.

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