Synthetic biology yields a dinuclear copper based antibody for the naked-eye detection of glyphosate

<div><div><div><p>The design and construction of synthetic antibodies capable of recognizing selectively antigens is an important challenge for synthetic biology and bio-engineering. Here, we develop a step towards the construction of de novo synthetic antibodies using a new combinatorial based approach. The bioconstruct incorporates supramolecularly a self assembling inorganic complex into a protein thus creating a modular and evolvable receptor. We used a dinuclear copper based inhibitor of carbonic anhydrase to program host-guest recognition, which in the presence of glyphosate generates a selective naked-eye sensing. The construct was used to detect the pesticide in complex samples. Taken together, our results provide new opportunities for the combinatorial optimization and evolution of our synthetic antibodies. Our assay is geared and designed specifically towards the mimic of natural antibodies but with features reminiscent of both synthetic biology and inorganic chemistry. In the near future, we anticipate evolution and artificial intelligence protocols dedicated to fine tune our host for the optimal recognition of a multitude of analytes.</p></div></div></div>

An explicitly designed paratope of Amyloid-β prevents neuronal apoptosis in vitro and hippocampal damage in rat brain

Synthetic antibodies hold great promise in combating diseases, diagnosis, and a wide range of biomedical applications. However, designing a therapeutically amenable, synthetic antibody that can arrest the aggregation of Amyloid-β...

Chemical Diversification of Simple Synthetic Antibodies

<p>Antibodies possess properties that make them valuable as therapeutics, diagnostics, and basic research tools. However, antibody chemical reactivity and covalent antigen binding are constrained, or even prevented, by the narrow range of chemistries encoded in the canonical amino acids. In this work, we investigate strategies for leveraging an expanded range of chemical functionality to augment antibody binding properties. Using yeast displayed antibodies, we explored the presentation of noncanonical amino acids (ncAAs) in or near antibody complementarity determining regions (CDRs) and evaluated the properties of the resulting constructs. To enable systematic characterization of ncAA incorporation sites, we first investigated whether diversification of a single antibody loop would support isolation of binding clones. We constructed a billion-member library containing canonical amino acid diversity and loop length diversity only within the 3rd complementarity determining region of the heavy chain (CDR-H3). Screens against a series of immunoglobulins from three species resulted in the isolation of antibodies exhibiting moderate affinities (double- to triple-digit nanomolar affinities) and, in several cases, single-species specificity. These findings confirmed that antibody specificity can be mediated by a single CDR. With this constrained diversity, we were able to utilize additional CDRs for the installation of chemically reactive and photo-crosslinkable ncAAs. Apparent binding affinities of ncAA-substituted synthetic antibodies on the yeast surface revealed that ncAA incorporation is generally well tolerated. However, changes in binding affinities did occur upon substitution, and varied based on factors including ncAA side chain identity, location of ncAA incorporation, and the ncAA incorporation machinery used. We further investigated chemical modifications facilitated by ncAA installation. Multiple azide-containing ncAAs supported both <a>copper-catalyzed azide-alkyne cycloaddition (CuAAC) and strain-promoted azide-alkyne cycloaddition </a>(SPAAC) without abrogation of binding function following the installation of bulky probes. Similarly, several alkyne substitutions facilitated CuAAC without apparent disruption of binding function. Finally, antibodies substituted with a photo-crosslinkable ncAA were evaluated for ultraviolet-mediated crosslinking on the yeast surface. Competition-based assays revealed position-dependent linkages that could not be displaced by excess soluble antigen, strongly suggesting successful crosslinking. Key findings regarding CuAAC reactions and photo-crosslinking on the yeast surface were confirmed using soluble forms of ncAA-substituted clones. These consistent behaviors between the yeast surface and in solution suggest that chemical diversification can be incorporated into yeast display screening approaches. Taken together, our results highlight the power of integrating the use of yeast display and ncAAs in search of proteins with “chemically augmented” binding functions. More specifically, our findings provide the means to productively integrate antibodies with ncAAs by leveraging simple synthetic antibodies. The efficient preparation and chemical diversification of antibodies on the yeast surface opens up new possibilities for discovering “drug-like” protein leads in high throughput.</p>

Chemical Diversification of Simple Synthetic Antibodies

<p>Antibodies possess properties that make them valuable as therapeutics, diagnostics, and basic research tools. However, antibody chemical reactivity and covalent antigen binding are constrained, or even prevented, by the narrow range of chemistries encoded in the canonical amino acids. In this work, we investigate strategies for leveraging an expanded range of chemical functionality to augment antibody binding properties. Using yeast displayed antibodies, we explored the presentation of noncanonical amino acids (ncAAs) in or near antibody complementarity determining regions (CDRs) and evaluated the properties of the resulting constructs. To enable systematic characterization of ncAA incorporation sites, we first investigated whether diversification of a single antibody loop would support isolation of binding clones. We constructed a billion-member library containing canonical amino acid diversity and loop length diversity only within the 3rd complementarity determining region of the heavy chain (CDR-H3). Screens against a series of immunoglobulins from three species resulted in the isolation of antibodies exhibiting moderate affinities (double- to triple-digit nanomolar affinities) and, in several cases, single-species specificity. These findings confirmed that antibody specificity can be mediated by a single CDR. With this constrained diversity, we were able to utilize additional CDRs for the installation of chemically reactive and photo-crosslinkable ncAAs. Apparent binding affinities of ncAA-substituted synthetic antibodies on the yeast surface revealed that ncAA incorporation is generally well tolerated. However, changes in binding affinities did occur upon substitution, and varied based on factors including ncAA side chain identity, location of ncAA incorporation, and the ncAA incorporation machinery used. We further investigated chemical modifications facilitated by ncAA installation. Multiple azide-containing ncAAs supported both <a>copper-catalyzed azide-alkyne cycloaddition (CuAAC) and strain-promoted azide-alkyne cycloaddition </a>(SPAAC) without abrogation of binding function following the installation of bulky probes. Similarly, several alkyne substitutions facilitated CuAAC without apparent disruption of binding function. Finally, antibodies substituted with a photo-crosslinkable ncAA were evaluated for ultraviolet-mediated crosslinking on the yeast surface. Competition-based assays revealed position-dependent linkages that could not be displaced by excess soluble antigen, strongly suggesting successful crosslinking. Key findings regarding CuAAC reactions and photo-crosslinking on the yeast surface were confirmed using soluble forms of ncAA-substituted clones. These consistent behaviors between the yeast surface and in solution suggest that chemical diversification can be incorporated into yeast display screening approaches. Taken together, our results highlight the power of integrating the use of yeast display and ncAAs in search of proteins with “chemically augmented” binding functions. More specifically, our findings provide the means to productively integrate antibodies with ncAAs by leveraging simple synthetic antibodies. The efficient preparation and chemical diversification of antibodies on the yeast surface opens up new possibilities for discovering “drug-like” protein leads in high throughput.</p>

Computational Recipe for Designing Antibodies against the Ebola Virus

A conceptual basis for antiviral therapy is to deliver a synthetic antibody that binds to a viral surface protein, and thus prevents the virus from deploying its cell-entry mechanism. The fast and untraceable virus mutations take lives of thousands of people before the immune system can produce the inhibitory antibody. In this paper, we devised a computational recipe to predict both the viral escape mutations and the possible inhibitory synthetic antibodies. We combined bioinformatics, structural biology, and molecular dynamics (MD) simulations to explore the most likely viral mutations and the candidate antibodies that can inhibit those escape mutations. Specifically, using the crystal structures of the Sudan and Zaire Ebola viral GPs in complex to their respective antibodies (ABs), we have performed an extensive set of MD simulations, both on the wild-type structures and on a large array of additional complexes designed and generated through combinatorial mutations. We discovered that our methods enabled the successful redesign of antibody sequences to essentially all likely glycoprotein mutations. Our findings and the computational methodology developed here for general antibody design can facilitate therapy of current and possibly next generations of viruses.Significance of the ManuscriptThis manuscript has high significance both methodologically and in potential biomedical application. In methodology, the manuscript combines molecular dynamics, Monte Carlo calculations, and bioinformatics in a novel way to simulate the evolutionary arms race between an evolving viral coat protein and a counter-evolving antibody against the virus. This simulation is shown to provide a method for designing a synthetic antibody against the newly emerging viral strains. This work is done in the context of ongoing work in other laboratories in which cells can be induced to produce synthetic antibodies and those synthetic antibodies can be edited (via, for example, CRISPR) to have an arbitrary sequence in the region that binds the viral coat protein. Putting those experimental methods together with the computational methods we present in this paper has the potential to provide a important approach to produce antibodies-on-demand against evolving viruses.