The present invention provides assays and assay systems for use in spatially encoded biological assays. The invention provides an assay system comprising an assay capable of high levels of multiplexing where reagents are provided to a biological sample in defined spatial patterns; instrumentation capable of controlled delivery of reagents according to the spatial patterns; and a decoding scheme providing a readout that is digital in nature.

Chemoproteomic methods for detecting and profiling electrophilic post-translational modifications (PTMs) and oxidative PTMs in proteins are described. The methods including contacting a proteomic mixture with a probe having hydrazine and an affinity handle to form a covalent linkage between the hydrazine moiety of the probe and the endogenous electrophilic PTM or the endogenous oxidative PTM. The resulting derivatized proteins are labelled with an tag via a click chemistry reaction. The labelled proteins can then be detected or profiled using techniques such as, for example, fluorescence imaging or mass spectrometry. Also described are protein conjugates having a covalent linkage formed by reaction of a hydrazine or oxyamine moiety of a probe with an electrophilic or oxidative PTM of a protein.

The present invention provides assays and assay systems for use in spatially encoded biological assays. The invention provides an assay system comprising an assay capable of high levels of multiplexing where reagents are provided to a biological sample in defined spatial patterns; instrumentation capable of controlled delivery of reagents according to the spatial patterns; and a decoding scheme providing a readout that is digital in nature.

The invention is a novel reporter system for measuring protein-protein interactions. The system uses a pair of functionalized coiled coil subunits that spontaneously form two separate homo-oligomers when expressed in cells. The coiled coil subunits are functionalized with fluorescent proteins and complementary interacting proteins. Upon an activation stimulus which promotes the protein-protein interaction, the interacting proteins drive the formation of multivalent aggregates of the homo-oligomers in phase-shifted droplets. The highly concentrated fluorescent proteins in these structures provide high brightness over background fluorescence and a readily observed, quantitative and dynamic indicator of the protein-protein interaction. The reporters and assay methods are amenable to cells and whole organisms.

A system for detecting the presence of and/or quantifying the amount or concentration of one or more analytes in a sample includes a flow assay cartridge having a multiplexed sensing membrane that has immunoreaction or biological reaction spots of varying conditions spatially arranged across the surface of the membrane defining an optimized spot map. A reader device is provided that uses a camera to image the multiplexed sensing membrane. Image processing software obtains normalized pixel intensity values of the plurality of immunoreaction or biological reaction spots and which are used as inputs to one or more trained neural networks configured to generate one or more outputs that: (i) quantify the amount or concentration of the one or more analytes in the sample; and/or (ii) indicate the presence of the one or more analytes in the sample; and/or (ii) determines a diagnostic decision or classification of the sample.

Provided herein are methods of identifying structures, e.g., attributes, of a therapeutic protein or a target that affect an interaction between the therapeutic protein and the target. In exemplary embodiments, the method comprises: (a) applying a stress to a first sample comprising therapeutic proteins or targets; (b) contacting the first sample with a second sample comprising targets or therapeutic proteins to form a mixture comprising (i) therapeutic protein-target complexes, (ii) unbound therapeutic proteins, and (iii) unbound targets; and (c) separating the mixture into at least two fractions, wherein an unbound fraction comprises unbound therapeutic proteins or unbound targets and a bound fraction comprises therapeutic protein-target complexes; and (d) for each of the unbound fraction and bound fraction, identifying and quantifying the abundance of the structures, e.g., attribute, present on a species of the therapeutic protein or target.

A method of solvent-induced protein precipitation (SIP) for detecting the interaction of ligands with proteins in a complex protein sample. After the equal amount of solvent is added to the protein samples with and without a ligand to denature and precipitate the proteins, the protein abundances in supernatant and/or precipitate in the ligand group and the control group are measured by quantitative technology. The target protein(s) of a ligand is/are determined by comparing the differences of protein abundances in the ligand group and the control group. The affinity between a ligand and its targets can be evaluated by dose dependent experiments. This method does not require the chemical modification of the ligand and has the feature of high specificity. Furthermore, in certain embodiments, the targets identified by SIP method are complementary to those identified by thermal proteome profiling (TPP) method.

Methods for the large scale identification of post-translational modification states of proteins and enzyme activities for carrying out post-translational modification reactions involve the analysis of functional extracts from fresh and frozen samples using protein arrays. The methods and kits of the present invention can be used to analyze and characterize compounds for their effects on post-translational modifications and their pathways. The methods and kits can also be used to diagnose and characterize a wide variety of diseases and medical conditions, including cancer, neurodegenerative diseases, immune diseases, infectious diseases, genetic diseases, metabolic conditions, and drug effects using cells or body fluids of a patient.

Provided herein is a platform technology for designing stabilized peptides that covalently bind their target protein and thereby inhibit the activity of the target protein. Also provided are exemplary stabilized peptides that can be used for covalent modification of their target proteins.

Disclosed herein are isolated compositions including at least 2 of mutant peptides selected from the group consisting of SEQ ID NOS: 1-149, or polypeptides comprising the mutant peptides; wherein the composition comprises mutant peptides encoded by 2 or more genes. Also disclosed are methods for personalized treatment of breast cancer involving creating a peptide array of mutant peptides comprising the mutations in protein-encoding regions of the high-frequency cancer genes or the exome in a subject and screening the peptide array with a biological sample from the subject to detect antibodies in the biological sample that bind to the array, to detect antigenic targets for therapy in treating the subject.