Peptide Sequence Determination of Cyclic Peptides

Cyclic peptides are bioactive substances with a ring-like structure formed by the connection of two or more amino acids through peptide bonds. Cyclic peptides have high structural stability and are not easily hydrolyzed by enzymes. Therefore, they have a very wide range of applications in biology, medicine, chemistry, drug research and development, and other fields. Knowing the peptide sequence of cyclic peptides is a key to understanding its structure and function and developing related drugs. The following will detail the methods for determining the peptide sequence of cyclic peptides and their applications in various fields.

 

Common Methods

1. Mass Spectrometry

Mass spectrometry is a common method used for determining the peptide sequence of cyclic peptides, including peptide-based sequencing and peptide-based sequencing. Peptide-based sequencing includes steps such as peptide cutting, peptide ionization, ion acceleration, and mass spectrometry analysis. Peptide-based sequencing requires the peptide to be decomposed in the mass spectrometer, and the peptide sequence is inferred by measuring the mass of its fragments.

 

2. Edman Degradation

This is a classic method for peptide sequence determination. The complete sequence of peptides can be obtained through continuous degradation of the N-terminal amino acids of the peptide. However, since cyclic peptides have no free N-termini, they need to be linearized first.

 

3. Liquid Phase Peptide Sequencing

This method mainly uses high-performance liquid chromatography combined with mass spectrometry, which can quickly and highly sensitively sequence peptides and proteins at high throughput.

 

Applications

1. Drug Development

Cyclic peptides play an important role in drug development, such as cyclosporine, vancomycin, etc. By determining the peptide sequence of cyclic peptides, their structure can be clarified, thereby designing drugs with specific biological activities.

 

2. In Situ Peptide Sequencing

The peptide sequence determination of cyclic peptides also has applications in in situ peptide sequencing. Through mass spectrometry imaging, the location and structural recognition of peptides and proteins in tissues or cells can be achieved.

 

3. Cyclic Peptide Structure and Function Research

The peptide sequence determination of cyclic peptides plays an important role in the study of cyclic peptide structure and function. By determining the peptide sequence of cyclic peptides, its possible three-dimensional structure can be inferred, thereby understanding its biological activity.

 

In summary, the peptide sequence determination of cyclic peptides is an indispensable part of current cyclic peptide research. It provides an important basis for us to understand the structure and function of cyclic peptides and to develop related drugs. With the advancement of technology, we look forward to more and more efficient methods for peptide sequence determination of cyclic peptides being developed in the future.