Compositions and methods for detecting nucleic acid-protein interactions, or more generally interactions between a nucleic acid and another molecule. A Cas protein (e.g., a catalytically dead Cas13) is fused to a proximity tagging enzyme (e.g., a Pup ligase) and thus brings the proximity tagging enzyme to the proximity of a protein that binds to a nucleic acid, when the Cas protein recognizes the nucleic acid, e.g., through a guide RNA. The proximity tagging enzyme then tags the protein enabling it to be identified as a protein that interacts with the nucleic acid.

The present disclosure is directed to RNA-regulated fusion proteins comprising a protein of interest and an RNA-regulated destabilization domain. Also disclosed are RNA aptamers that bind specifically to a RNA-regulated destabilization domain. Nucleic acid molecules encoding the RNA-regulated fusion proteins and RNA aptamers and methods of use thereof are also disclosed.

The present invention provides an ascorbate peroxidase mutant MaAPX1.sup.M36K and an application thereof, belonging to the technical field of biotechnology. An amino acid sequence of the mutant MaAPX1.sup.M36K of the present invention is shown in SEQ ID NO. 3. In the present invention, the mutant MaAPX1.sup.M36K reconstruction protein is obtained by the method of prokaryotic expression. It is found that the mutant MaAPX1.sup.M36K improves catalytic efficiency by nearly 5 times, providing a technical reference for further study and application of APX1.

The present invention provides an ascorbate peroxidase mutant MaAPX1.sup.M36K and an application thereof, belonging to the technical field of biotechnology. An amino acid sequence of the mutant MaAPX1.sup.M36K of the present invention is shown in SEQ ID NO. 3. In the present invention, the mutant MaAPX1.sup.M36K reconstruction protein is obtained by the method of prokaryotic expression. It is found that the mutant MaAPX1.sup.M36K improves catalytic efficiency by nearly 5 times, providing a technical reference for further study and application of APX1.

The present invention provides fusion proteins, polynucleotides, kits, as well as TALE- or CRISPR-Cas based systems and methods. The present invention relies on proximity-dependent biotinylation, which allows site-directed protein or DNA purification and identification. The present invention provides tools for delineating the genetics of disease mechanism and for the identification of therapeutic targets and markers.

The present invention relates to a transgenic animal in which APEX2 is specifically expressed in a mitochondrial matrix and to uses thereof. When the transgenic animal according to the present invention is used, it is possible to overcome the limitation of being susceptible to contamination with proteins derived from other organelles or other tissue cells in existing mitochondrial proteomic studies. Accordingly, mitochondrial matrix proteomic research with a high reliability is possible, tissue-specific mitochondrial matrix proteomics can easily be analyzed, and a wide range of applications are possible in basic life science research, drug development, and diagnostic research related to mitochondrial proteomics.

The present invention provides fusion proteins, polynucleotides, kits, as well as TALE- or CRISPR-Cas based systems and methods. The present invention relies on proximity-dependent biotinylation, which allows site-directed protein or DNA purification and identification. The present invention provides tools for delineating the genetics of disease mechanism and for the identification of therapeutic targets and markers.

An imaging method comprising expressing in cells a Class I heme peroxidase, which optionally is fused with a protein of interest or a cellular localization signal peptide, and contacting the cells with a substrate of the Class I heme peroxidase to allow conversion of the substrate into a product via an oxidation reaction catalyzed by the Class I heme peroxidase, wherein the product releases a signal detectable by a microscope such as an electron microscope. Also disclosed herein are monomeric mutants of a Class I heme peroxidase and mutants of the enzyme that exhibit elevated enzymatic activity as compared to the corresponding wild-type counterpart.

Compounds useful for biotin-free proximity labeling are provided. Also provided are methods for biotin-free labeling of biomolecules in proximity to a target in a cell, which involve attaching an engineered labeling enzyme to the target; and contacting the cell to a compound as disclosed, which is a substrate of the engineered labeling enzyme and which includes a label moiety, wherein the biomolecules in proximity to the target are labeled.

The present disclosure is directed to RNA-regulated fusion proteins comprising a protein of interest and an RNA-regulated destabilization domain. Also disclosed are RNA aptamers that bind specifically to a RNA-regulated destabilization domain. Nucleic acid molecules encoding the RNA-regulated fusion proteins and RNA aptamers and methods of use thereof are also disclosed.