Overview of Methods for Protein Amino Acid Sequence Detection

The detection of protein amino acid sequences aims to determine a protein's primary structure, which is the linear arrangement of amino acids composing the protein. Understanding this primary structure is akin to deciphering the genetic code of the protein, and it holds massive significance across various scientific disciplines. Below are some commonly used methods for detecting protein amino acid sequences.

 

Edman Degradation

Edman degradation is one of the earliest methods for protein sequencing and is a traditional chemical method. The method sequentially removes amino acids from the N-terminal of a protein or peptide, identifying the amino acid removed at each step.Though this method can consecutively determine 20-30 amino acids, it might need to be combined with other methods for long-chain proteins.

 

Mass Spectrometry

Mass spectrometry has become a powerful tool for protein sequencing. It leverages the mass and charge characteristics of proteins or peptides, analyzing them through a mass spectrometer to determine their amino acid composition.

 

When coupled with specific protease digestion, mass spectrometry can be used to infer the amino acid sequence of a protein. Modern tandem mass spectrometry techniques (like LC-MS/MS) offer high-resolution and highly sensitive protein sequence information.

 

Gene Sequencing

The latest advances in Next-Generation Sequencing (NGS) have expanded its application scope from genomics to proteomics. NGS-based methods, like RNA-seq and ribosome profiling, can infer protein sequences indirectly by analyzing the corresponding mRNA sequences.

 

Each of these methods has its advantages and limitations. Edman degradation can provide accurate results for small proteins but requires a considerable amount of sample. Mass spectrometry is versatile, capable of analyzing complex mixtures, but it might struggle with membrane proteins. NGS offers high-throughput capability but relies on mRNA data, possibly not providing direct protein sequence information.