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Cystatin. Amino acid sequence and possible secondary structure
The Biochemical Journal
|February 1, 1984
Summary
Researchers determined the amino acid sequence of chicken cystatin, a protein inhibiting cysteine proteinases. Structural analysis revealed it contains mainly beta-structure, with minimal alpha-helix content.
Area of Science:
- Biochemistry
- Structural Biology
- Proteomics
Background:
- Cystatin is a protein found in chicken egg-white.
- It acts as a tight-binding inhibitor for various cysteine proteinases.
- Understanding its structure is crucial for proteinase inhibition studies.
Purpose of the Study:
- To determine the complete amino acid sequence of chicken cystatin.
- To analyze the secondary structure of cystatin.
- To compare the cystatin sequence with other known protein sequences.
Main Methods:
- Amino acid sequencing.
- Computer analysis of the sequence.
- Circular dichroism (c.d.) spectrometry for secondary structure determination.
Main Results:
- The amino acid sequence of cystatin was determined, comprising 116 residues.
- The calculated molecular weight (Mr) is 13,143.
- No significant similarity was found between cystatin and other known protein sequences.
- Secondary structure analysis indicated approximately 20% alpha-helix and a predominantly beta-structure.
Conclusions:
- The primary structure of chicken cystatin has been elucidated.
- Cystatin possesses a unique structure with a high proportion of beta-structure.
- The determined sequence and structural features provide a basis for understanding its inhibitory mechanism against cysteine proteinases.