Project description:A comprehensive analysis of the phosphoproteome is essential for understanding molecular mechanisms of human diseases. However, current tools to enrich phosphotyrosine are limited in their applicability and scope. Here, we engineered new superbinder SH2 domains that enrich diverse sets of phosphotyrosine peptides. We used phage display to select a Fes SH2 domain variant with high affinity for phosphotyrosine (superFes-SH2, sFes1) and solved the structure of sFes1 bound to a phosphopeptide. We performed systematic structure-function analyses of the superbinding mechanisms of sFes1 and superSrc-SH2 (sSrc1), another SH2-superbinder. We grafted the superbinder motifs from sFes1 and sSrc1 into 17 additional SH2 domains and confirmed increased binding affinity for specific phosphopeptides. Using mass spectrometry, we demonstrated that SH2 superbinders have distinct specificity profiles and superior capabilities to enrich phosphotyrosine peptides. Finally, combinations of SH2 superbinders as affinity purification tools showed that unique subsets of phosphopeptides can be enriched with unparalleled depth and coverage.
Project description:IgNAR exhibits significant promise in the fields of cancer and anti-virus biotherapies. Notably, the variable regions of IgNAR (VNAR) possess comparable antigen binding affinity with much smaller molecular weight (~12 kDa) compared to IgNAR. Antigen specific VNAR screening is a changeling work, which limits its application in medicine and therapy fields. Though phage display is a powerful tool for VNAR screening, it has a lot of drawbacks, such as small library coverage, low expression levels, unstable target protein, complicating and time-consuming procedures. Here we report VNAR screening with next generation sequencing (NGS) could effectively overcome the limitations of phage display, and we successfully identified approximately 3000 BAFF-specific VNARs in Chiloscyllium plagiosum vaccinated with the BAFF antigen. The results of modelling and molecular dynamics simulation and ELISA assay demonstrated that one out of the top five abundant specific VNARs exhibited higher binding affinity to the BAFF antigen than those obtained through phage display screening. Our data indicates NGS would be an alternative way for VNAR screening with plenty of advantages.
Project description:Display technologies, e.g., phage, ribosome, mRNA, bacterial, and yeast-display, combine high content peptide libraries with appropriate screening strategies to identify functional peptide sequences. Construction of large peptide library and display-screen system in intact mammalian cells will facilitate the development of peptide therapeutics targeting transmembrane proteins. Our previous work established linear-double-stranded DNAs (ldsDNAs) as innovative biological parts to implement AND gate genetic circuits in mammalian cell line. In the current study, we employ ldsDNA with terminal NNK degenerate codons as AND gate input to build highly diverse peptide library in mammalian cells. Only PCR reaction and cell transfection experiments are needed to construct the library. High-throughput sequencing (HTS) results reveal that our new strategy could generate peptide library with both amino acid sequence and peptide length diversities. Our work establishes ldsDNA as biological parts for building highly diverse peptide library in mammalian cells, which shows great application potential in developing therapeutic peptides targeting transmembrane proteins.
Project description:Multi-modal measurements of single cell profiles are a powerful tool for characterizing cell states and regulatory mechanisms. While current methods allow profiling of RNA along with either readouts of chromatin or protein, connecting chromatin state to protein levels remains a barrier. Here, we developed PHAGE-ATAC, a method that uses engineered camelid single-domain antibody (‘nanobody’)-displaying phages for simultaneous single-cell measurement of surface proteins, chromatin accessibility profiles, and mtDNA-based clonal tracing through a single-cell and massively parallel droplet-based assay of transposase-accessible chromatin with sequencing (ATAC-seq). We demonstrate PHAGE-ATAC for multimodal analysis in primary human immune cells, for multiplexing, for intracellular protein analysis, and for the detection of SARS-CoV-2 spike protein. Finally, we construct a synthetic high-complexity phage library for selection of novel antigen-specific nanobodies that bind cells of particular molecular profiles, opening a new avenue for protein detection, cell characterization and screening with single-cell genomics.
Project description:Multi-modal measurements of single cell profiles are a powerful tool for characterizing cell states and regulatory mechanisms. While current methods allow profiling of RNA along with either readouts of chromatin or protein, connecting chromatin state to protein levels remains a barrier. Here, we developed PHAGE-ATAC, a method that uses engineered camelid single-domain antibody (‘nanobody’)-displaying phages for simultaneous single-cell measurement of surface proteins, chromatin accessibility profiles, and mtDNA-based clonal tracing through a single-cell and massively parallel droplet-based assay of transposase-accessible chromatin with sequencing (ATAC-seq). We demonstrate PHAGE-ATAC for multimodal analysis in primary human immune cells, for multiplexing, for intracellular protein analysis, and for the detection of SARS-CoV-2 spike protein. Finally, we construct a synthetic high-complexity phage library for selection of novel antigen-specific nanobodies that bind cells of particular molecular profiles, opening a new avenue for protein detection, cell characterization and screening with single-cell genomics.
Project description:Multi-modal measurements of single cell profiles are a powerful tool for characterizing cell states and regulatory mechanisms. While current methods allow profiling of RNA along with either readouts of chromatin or protein, connecting chromatin state to protein levels remains a barrier. Here, we developed PHAGE-ATAC, a method that uses engineered camelid single-domain antibody (‘nanobody’)-displaying phages for simultaneous single-cell measurement of surface proteins, chromatin accessibility profiles, and mtDNA-based clonal tracing through a single-cell and massively parallel droplet-based assay of transposase-accessible chromatin with sequencing (ATAC-seq). We demonstrate PHAGE-ATAC for multimodal analysis in primary human immune cells, for multiplexing, for intracellular protein analysis, and for the detection of SARS-CoV-2 spike protein. Finally, we construct a synthetic high-complexity phage library for selection of novel antigen-specific nanobodies that bind cells of particular molecular profiles, opening a new avenue for protein detection, cell characterization and screening with single-cell genomics.
Project description:High-density phage epitope microarray from 31 samples were used for unsupervised analysis (GSM36153...GSM36183). 129 samples from prostate cancer patients and controls were screened on small focused epitope chips, which contained 180 phage elements. These data were used to train GA/KNN program (GSM36184...GSM36312). 128 samples from localized prostate cancer patients and controls were screened on small focused epitope chips. These independent data were used to validate the epitomic profile (GSM36313...GSM36375, GSM40203...GSM40213, GSM40216, GSM40218, GSM40219, GSM40222, GSM40225, GSM40227, GSM40229, GSM40233, GSM40237, GSM40246...GSM40294). Three subgroups of samples were used as test sets to validate the specificity of epitomic profile (GSM36376...GSM36410, GSM40214, GSM40215, GSM40217, GSM40220, GSM40221, GSM40224, GSM40226, GSM40228, GSM40231, GSM40234...GSM40236, GSM40238...GSM40244). Project----Identification of humoral signature for prostate cancer diagnosis We constructed a prostate cancer cDNA phage display library. cDNAs were reverse-synthesized from mDNA pool isolated from prostate cancer tissues. Enzyme-digested cDNA fragments were then inserted into phage vector to make a whole prostate cancer phage expressed cDNA library. In order to select cancer specific phage epitope from this library, we performed several cycles of affinity enrichment. We used the bounded IgG pool isolated from prostate cancer patient sera to select the tumor specific phage epitope clones. Once we had the enriched phage epitope library, we cultured the phage library on LB-agar dish for individual phage colonies. About 2300 phage colonies from agar dish were picked up using toothstick and cultured in 96-well microtiter plates. Each clone was labeled as microtiter plate #, column #, row#, i.e. clone ID. These 2300 clones were then spotted on slides in single spot (no any duplicate), i.e. each spot (labeled by clone ID) represents a single phage clone. The phage epitope microarrays were then screened using cancer or control sera. We employed two color system. Cy5-anti human IgG was to detect human IgG. For green color, we used Cy3-labeled anti-phage capsid protein as internal reference to normalize the ammount difference of phage particles spotted on each spot. Thus the ratio of Cy5/Cy3 would count for the immune response in cancer or control sera. Once we identified humoral signature in prostate cancer patients, we could sequence the phage clone to characterize the nature of the genes or proteins.