Disclosed herein are methods, compositions, probes, polypeptides, assays, and kits for identifying a cysteine containing protein as a binding target for a small molecule fragment. Also disclosed herein are methods, compositions, and probes for mapping a biologically active cysteine site on a protein and screening a small molecule fragment for interaction with a cysteine containing protein.

The present disclosure provides methods and compositions for the production of chimeric antibodies that specifically bind an antigen of interest.

A method of determining the activation energy E.sub.a for degradation of a chemical species includes in sequence the steps of a) simultaneously incubating a plurality of samples of the chemical species in a single unitary device at a plurality of constant temperatures T, in each case for an incubation time t selected to result in loss of at most 20 mol % of the amount originally present; b) quenching each of the samples to stop degradation; c) determining the mole fraction m of the chemical species remaining in each of the quenched samples, relative to the amount present before incubating; d) determining for each sample a reaction rate coefficient k.sub.obs according to the equation $k_{\mathrm{obs}}\left(T\right)=\frac{1-m\left(T\right)}{t};$
and e) performing numerical regression of the k.sub.obs values obtained in step d) and the corresponding temperatures T in K to derive the activation energy E.sub.a according to the following equation $k_{\mathrm{obs}}=k_0\exp \left(\frac{E_a}{R}\left(\frac{1}{T}-\frac{1}{T_0}\right)\right),$
or to derive a temperature-dependent activation energy if that is more appropriate for the chemical species of interest.

The invention relates to an epitope protection assay for use in diagnosis, prognosis and therapeutic intervention in diseases, for example, involving polypeptide aggregation, such as prion infections. The methods of the invention first block accessible polypeptide target epitope with a blocking agent. After denaturation of the polypeptide, a detecting agent is used to detect protein with target epitope that was inaccessible during contact with the blocking agent. The invention also relates to novel amyotrophic lateral sclerosis-specific epitopes and their uses to make antibodies, and to the novel antibodies and uses thereof.

The present disclosure provides methods and reagents useful for analyzing protein-protein interfaces such as interfaces between a presenter protein (e.g., a member of the FKBP family, a member of the cyclophilin family, or PIN1) and a target protein. In some embodiments, the target and/or presenter proteins are intracellular proteins. In some embodiments, the target and/or presenter proteins are mammalian proteins.

A method for cell-free protein synthesis is characterized in that pH is controlled by using an enzyme. For example, by using an amino acid decarboxylase, the pH is controlled according to removal of hydrogen ions that are produced during regeneration of ATP. The method for cell-free protein synthesis of the present invention has an advantage that not only the expression amount of protein is enhanced but also the expressed protein can be directly used for activity analysis without undergoing any separation or purification.

Methods for proteomic screening on random protein-bead arrays by mass spec is described. Photocleavable mass tags are utilized to code a protein library (bait molecules) displayed on beads randomly arrayed in an array substrate. A library of probes (prey) can be mixed with the protein-bead array to query the array. Because mass spec can detect multiple mass tags, it is possible to rapidly identify all of the interactions resulting from this mixing.

The invention pertains, at least in part, to a method for forming an ordered structure of amphiphilic molecules, such as proteins. The method includes contacting a population of amphiphilic molecules with an interface; compressing said population laterally to an appropriate pressure, such that an ordered structure at the interface is formed. The invention also pertains to the two- and three-dimensional ordered structures that are formed using the planar membrane compression method of the invention.

A method for analyzing a biological sample by antibody profiling for identifying forensic samples or for detecting the presence of an analyte. In an embodiment of the invention, the analyte is a drug, such as marijuana, Cocaine (crystalline tropane alkaloid), methamphetamine, methyltestosterone, or mesterolone. The method comprises attaching antigens to a surface of a solid support in a preselected pattern to form an array wherein locations of the antigens are known; contacting the array with the biological sample such that a portion of antibodies in the sample reacts with and binds to the antigens in the array to form immune complexes; washing away antibodies that do form immune complexes; and detecting the immune complexes, to form an antibody profile. Forensic samples are identified by comparing a sample from an unknown source with a sample from a known source. Further, an assay, such as a test for illegal drug use, can be coupled to a test for identity such that the results of the assay can be positively correlated to the subject's identity.

The present disclosure provides modified antibodies which contain an antibody or antibody fragment (AB) modified with a masking moiety (MM). Such modified antibodies can be further coupled to a cleavable moiety (CM), resulting in activatable antibodies (AAs), wherein the CM is capable of being cleaved, reduced, photolysed, or otherwise modified. AAs can exhibit an activatable conformation such that the AB is more accessible to a target after, for example, removal of the MM by cleavage, reduction, or photolysis of the CM in the presence of an agent capable of cleaving, reducing, or photolysing the CM. The disclosure further provides methods of making and using such modified antibodies and activatable antibodies.