How does the proximity ligation assay (PLA) differ from other methods used to detect protein-protein interactions?5 answersThe proximity ligation assay (PLA) stands out from other methods for detecting protein-protein interactions due to its ability to infer interactions in situ with high signal-to-noise ratio. PLA utilizes primary antibodies against the proteins of interest, allowing for the detection of proteins within 40 nm proximity in tissues. In contrast, proximity labeling (PL) involves attaching a catalyst to a protein of interest, which tags nearby proteins for identification, offering insights into proteomes with high spatial resolution. Additionally, a modified version of PLA, known as IPNR-PLA, enables the visualization of protein interactions with nascent RNA in single cells, providing a sensitive and quantitative approach for biological studies. These variations in PLA and related techniques showcase the diverse applications and advantages of each method in studying protein-protein interactions.
How to characterize multiprotein complexes and protein–protein interactions to identify proteins surrounding post-translationally modified proteins?5 answersProximity labeling catalyzed by promiscuous enzymes, such as APEX2, is a powerful approach to characterize multiprotein complexes and protein-protein interactions. However, current methods depend on the expression of exogenous fusion proteins and cannot be applied to post-translational modifications. To address this limitation, a new method called antibody-mediated protein A-APEX2 labeling (AMAPEX) has been developed. In this method, a modified protein is bound in situ by a specific antibody, which then tethers a protein A-APEX2 fusion protein. Activation of APEX2 labels the nearby proteins with biotin, which are then purified and identified by mass spectrometry. This approach has been successfully used to profile the binding proteins of histone modifications and verify their colocalization with bait proteins.
Whole proteome mapping of compound-protein interactions5 answersProteome-wide mapping of compound-protein interactions can be achieved using a combination of chemical similarity principles and deep learning. This approach involves identifying the targets of bioactive molecules by matching them with chemically similar annotated "bait" compounds and ranking them using deep learning algorithms. A user-friendly web server called DRIFT has been developed for high-throughput, multi-ligand target identification based on chemical similarity. Additionally, chemoproteomic technologies have emerged as a powerful strategy for assessing proteome-wide interactions of reactive small-molecules directly in complex biological systems. These technologies enable the identification of specific protein targets of covalent compounds, providing insights into their biological action, off-target effects, and potential toxicological liabilities. Overall, these methods and technologies contribute to the comprehensive mapping of compound-protein interactions at the proteome level.
How to find interaction of a drug to whole proteome in silico?5 answersIn silico methods can be used to find the interaction of a drug with the whole proteome. One approach is to create a heterogeneous biological graph of drugs and proteins and calculate personalized PageRank scores of drug nodes in the graph. Another strategy is to explore multiple strategies, such as finding binding hot spots, incorporating chemical similarity and bioactivity data, and sampling similar binding sites from homologous protein complexes. Additionally, in silico structure-based approaches can be used to discover small molecules that bind to protein-protein interaction (PPI) interfaces. These approaches take into account the characteristics of PPI interfaces, such as their large interface regions, flat geometry, and hydrophobic atom interactions. By applying these methods, researchers can gain insights into drug-protein interactions and potentially identify new drug targets within the proteome.
What is the most recent method for detecting protein-protein interactions?4 answersThe most recent method for detecting protein-protein interactions is a PDf (protein dimerization footprinting) method based on a nucleotide sequence. This method utilizes the influence of the interaction of target proteins on the combined structural domain of DNAs fused by the protein and the combination dynamics of a corresponding special DNA sequence. By representing the interaction of the target protein with the corresponding special DNA sequence, the method can determine the strength of the protein interaction based on the copy number of the special DNA sequence.
Where can I detect if two sequence hybridize to each other?4 answersHybridization between two sequences can be detected using different methods. One approach is through cooperative hybridization using high-density oligonucleotide arrays, where physical linkage between two loci on a DNA strand can be established. Another method involves detecting nucleic acid sequence aberrations by immobilizing hybridization probes to isolate specific nucleic acid sequences, indicating the presence of a sequence aberration. Additionally, an analog circuit design has been developed that can learn to detect a temporal sequence of two inputs, emitting a signal upon correct recognition. These methods provide ways to detect hybridization between two sequences in various contexts.