scholarly journals Toward machine-guided design of proteins

2018 ◽  
Author(s):  
Surojit Biswas ◽  
Gleb Kuznetsov ◽  
Pierce J. Ogden ◽  
Nicholas J. Conway ◽  
Ryan P. Adams ◽  
...  
Keyword(s):  
Directed Evolution ◽  
High Throughput ◽  
Protein Design ◽  
Protein Function ◽  
High Throughput Screening ◽  
Fluorescent Protein ◽  
Fitness Landscape ◽  
Optimization Strategy ◽  
Local Maxima ◽  
Green Fluorescent

AbstractProteins—molecular machines that underpin all biological life—are of significant therapeutic and industrial value. Directed evolution is a high-throughput experimental approach for improving protein function, but has difficulty escaping local maxima in the fitness landscape. Here, we investigate how supervised learning in a closed loop with DNA synthesis and high-throughput screening can be used to improve protein design. Using the green fluorescent protein (GFP) as an illustrative example, we demonstrate the opportunities and challenges of generating training datasets conducive to selecting strongly generalizing models. With prospectively designed wet lab experiments, we then validate that these models can generalize to unseen regions of the fitness landscape, even when constrained to explore combinations of non-trivial mutations. Taken together, this suggests a hybrid optimization strategy for protein design in which a predictive model is used to explore difficult-to-access but promising regions of the fitness landscape that directed evolution can then exploit at scale.

High Throughput Studies of Gene Expression Using Green Fluorescent Protein-Oxidative Stress Promoter Probe Constructs The Potential for Living Chips

2001 ◽  
Vol 6 (6) ◽  
pp. 421-428
Author(s):  
C. Renee Albano ◽  
Canghai Lu ◽  
William E. Bentley ◽  
Govind Rao
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Green Fluorescent Protein ◽  
High Throughput ◽  
High Throughput Screening ◽  
Fluorescent Protein ◽  
Chip Technology ◽  
Great Specificity ◽  
Green Fluorescent ◽  
Stress Promoter

Green fluorescent protein fusions were constructed with several oxidative stress promoters from Escherichia coli. These promoters were chosen for their induction by reactive oxygen species (ROS) such as superoxide, hydrogen peroxide, and hydroxyl radicals. When exposed to various free radical insults, the cells fluoresced with great specificity based on the corresponding ROS. In this work, we propose a way in which these constructs could be used to study the mode of action of a variety of antitumor drugs. This approach offers the possibility of complementing gene chip technology by the creation of living chips for high throughput screening as well as studying differential gene expression.

scholarly journals A Fluorescent-Based High-Throughput Screening Assay for Small Molecules That Inhibit the Interaction of MdmX with p53

2012 ◽  
Vol 18 (2) ◽  
pp. 191-198 ◽  
Author(s):  
Keiko Tsuganezawa ◽  
Yukari Nakagawa ◽  
Miki Kato ◽  
Shigenao Taruya ◽  
Fumio Takahashi ◽  
...  
Keyword(s):  
Small Molecules ◽  
High Throughput ◽  
High Throughput Screening ◽  
Fluorescent Protein ◽  
Diffusion Time ◽  
Correlation Spectroscopy ◽  
Screening Assay ◽  
High Throughput Screening Assay ◽  
Green Fluorescent ◽  
Fluorescence Quencher

A fluorescent-based high-throughput screening (HTS) assay for small molecules that inhibit the interaction of MdmX with p53 was developed and applied to identify new inhibitors. The assay evaluated the MdmX-p53 interaction by detecting the quenching of the fluorescence of green fluorescent protein (GFP) fused to the MdmX protein, after its interaction with a p53 peptide labeled with a fluorescence quencher. In this report, the developed HTS assay was applied to about 40 000 compounds, and 255 hit compounds that abrogated the GFP quenching were selected. Next, the obtained hits were reevaluated by other assays. First, their effects on the diffusion time of a fluorescently-labeled p53 peptide after incubation with the MdmX protein were tested by measuring the diffusion time using fluorescence correlation spectroscopy, and six stable hit compounds with IC50 values less than 5 µM were selected. Next, we further confirmed their inhibition of the MdmX-p53 interaction by surface plasmon resonance. To indicate the efficacy of the hit compound as a candidate anticancer drug, we showed that the hit compound triggered apoptosis after p53 and p21 accumulation in cultured MV4;11 leukemia cells. Thus, the new HTS assay is effective for obtaining novel MdmX-p53 interaction inhibitors that are valuable as candidate compounds for cancer treatment.

scholarly journals Improved Green Fluorescent Protein Reporter Gene-Based Microplate Screening for Antituberculosis Compounds by Utilizing an Acetamidase Promoter

2003 ◽  
Vol 47 (12) ◽  
pp. 3682-3687 ◽  
Author(s):  
Chartchai Changsen ◽  
Scott G. Franzblau ◽  
Prasit Palittapongarnpim
Keyword(s):  
Green Fluorescent Protein ◽  
High Throughput ◽  
High Throughput Screening ◽  
Antimicrobial Agents ◽  
Fluorescent Protein ◽  
Signal To Noise Ratio ◽  
Enhanced Fluorescence ◽  
Signal To Noise ◽  
Green Fluorescent ◽  
Fluorescent Protein Reporter

ABSTRACT The green fluorescent protein (GFP) gene offers many advantages as a viability reporter for high-throughput antimicrobial drug screening. However, screening for antituberculosis compounds by using GFP driven by the heat shock promoter, hsp60, has been of limited utility due to the low signal-to-noise ratio. Therefore, an alternative promoter was evaluated for its enhanced fluorescence during microplate-based culture and its response to 18 established antimicrobial agents by using a green fluorescent protein microplate assay (GFPMA). Mycobacterium tuberculosis strains H37Rv, H37Ra, and Erdman were transformed with pFPCA1, which contains a red-shifted gfp gene driven by the acetamidase promoter of M. smegmatis mc2155. The pFPCA1 transformants achieved higher levels of GFP-mediated fluorescence than those carrying the hsp60 construct, with signal-to-noise ratios of 20.6 to 27.8 and 3.8 to 4.5, respectively. The MICs of 18 established antimicrobial agents for all strains carrying pFPCA1 in the GFPMA were within 1 to 2 twofold dilutions of those determined by either the fluorometric or the visual microplate Alamar Blue assay (MABA). No significant differences in MICs were observed between wild-type and pFPCA1 transformants by MABA. The optimized GFPMA is sufficiently simple, robust, and inexpensive (no reagent costs) to be used for routine high-throughput screening for antituberculosis compounds.

scholarly journals Measuring the subcellular compartmentalization of viral infections by protein complementation assay

2021 ◽  
Vol 118 (2) ◽  
pp. e2010524118
Author(s):  
Juliette Fernandez ◽  
Cédric Hassen-Khodja ◽  
Virginie Georget ◽  
Thierry Rose ◽  
Yves Jacob ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Fluorescent Protein ◽  
Viral Infections ◽  
Nuclear Pore ◽  
Complementation Assay ◽  
Recent Emergence ◽  
Protein Complementation Assay ◽  
Green Fluorescent ◽  
Protein Complementation

The recent emergence and reemergence of viruses in the human population has highlighted the need to develop broader panels of therapeutic molecules. High-throughput screening assays opening access to untargeted steps of the viral replication cycle will provide powerful leverage to identify innovative antiviral molecules. We report here the development of an innovative protein complementation assay, termed αCentauri, to measure viral translocation between subcellular compartments. As a proof of concept, the Centauri fragment was either tethered to the nuclear pore complex or sequestered in the nucleus, while the complementary α fragment (<16 amino acids) was attached to the integrase proteins of infectious HIV-1. The translocation of viral ribonucleoproteins from the cytoplasm to the nuclear envelope or to the nucleoplasm efficiently reconstituted superfolder green fluorescent protein or NanoLuc αCentauri reporters. These fluorescence- or bioluminescence-based assays offer a robust readout of specific steps of viral infection in a multiwell format that is compatible for high-throughput screening and is validated by a short hairpin RNA-based prototype screen.

scholarly journals Droplet Microfluidics-Enabled High-Throughput Screening for Protein Engineering

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 734 ◽  
Author(s):  
Lindong Weng ◽  
James E. Spoonamore
Keyword(s):  
Protein Engineering ◽  
Directed Evolution ◽  
High Throughput ◽  
Protein Design ◽  
High Throughput Screening ◽  
Fluid Phase ◽  
Droplet Microfluidics ◽  
New Paradigm ◽  
Wide Range ◽  
Challenges And Opportunities

Protein engineering—the process of developing useful or valuable proteins—has successfully created a wide range of proteins tailored to specific agricultural, industrial, and biomedical applications. Protein engineering may rely on rational techniques informed by structural models, phylogenic information, or computational methods or it may rely upon random techniques such as chemical mutation, DNA shuffling, error prone polymerase chain reaction (PCR), etc. The increasing capabilities of rational protein design coupled to the rapid production of large variant libraries have seriously challenged the capacity of traditional screening and selection techniques. Similarly, random approaches based on directed evolution, which relies on the Darwinian principles of mutation and selection to steer proteins toward desired traits, also requires the screening of very large libraries of mutants to be truly effective. For either rational or random approaches, the highest possible screening throughput facilitates efficient protein engineering strategies. In the last decade, high-throughput screening (HTS) for protein engineering has been leveraging the emerging technologies of droplet microfluidics. Droplet microfluidics, featuring controlled formation and manipulation of nano- to femtoliter droplets of one fluid phase in another, has presented a new paradigm for screening, providing increased throughput, reduced reagent volume, and scalability. We review here the recent droplet microfluidics-based HTS systems developed for protein engineering, particularly directed evolution. The current review can also serve as a tutorial guide for protein engineers and molecular biologists who need a droplet microfluidics-based HTS system for their specific applications but may not have prior knowledge about microfluidics. In the end, several challenges and opportunities are identified to motivate the continued innovation of microfluidics with implications for protein engineering.

scholarly journals Identification of Novel Inhibitors of the Type I Interferon Induction Pathway Using Cell-Based High-Throughput Screening

2016 ◽  
Vol 21 (9) ◽  
pp. 978-988 ◽  
Author(s):  
Zoe O. Gage ◽  
Andri Vasou ◽  
David W. Gray ◽  
Richard E. Randall ◽  
Catherine S. Adamson
Keyword(s):  
Small Molecules ◽  
Reporter Gene ◽  
High Throughput ◽  
High Throughput Screening ◽  
Fluorescent Protein ◽  
Type I Interferon ◽  
Type I ◽  
Egfp Reporter Gene ◽  
Egfp Reporter ◽  
Green Fluorescent

Production of type I interferon (IFN) is an essential component of the innate immune response against invading pathogens. However, its production must be tightly regulated to avoid harmful effects. Compounds that modulate the IFN response are potentially valuable for a variety of applications due to IFN’s beneficial and detrimental roles. We developed and executed a cell-based high-throughput screen (HTS) targeting components that participate in and/or regulate the IRF3 and nuclear factor (NF)–κB branches of the IFN induction pathway. The assay detects activation of the IFN induction pathway via an enhanced green fluorescent protein (eGFP) reporter gene under the control of the IFNβ promoter and was optimized, miniaturized, and demonstrated suitable for HTS as robust Z′ factor scores of >0.6 were consistently achieved. A diversity screening set of 15,667 small molecules was assayed and two novel hit compounds validated that specifically inhibit the IFN induction pathway. We demonstrate that one of these compounds acts at or upstream of IRF3 phosphorylation. A second cell-based assay to detect activation of the IFN signaling (Jak-Stat) pathway via an eGFP reporter gene under the control of an IFN-stimulated response element (ISRE) containing MxA promoter also performed well (robust Z′ factor >0.7) and may therefore be similarly used to identify small molecules that modulate the IFN signaling pathway.

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