The primary structure of hen ovotransferrin

Area of Science:

• Biochemistry
• Molecular Biology
• Protein Chemistry

Background:

• Ovotransferrin, a key protein in egg white, plays crucial roles in iron transport and antimicrobial defense.
• Understanding its precise amino acid sequence and structure is vital for elucidating its functions.

Purpose of the Study:

• To compare experimentally derived peptide sequences of hen ovotransferrin with its complete amino acid sequence.
• To analyze the structural similarities between the two halves of the ovotransferrin molecule.
• To investigate the evolutionary relationship between hen and human transferrins.

Main Methods:

• Peptide sequencing of hen ovotransferrin.
• Comparison with complete amino acid sequence derived from cDNA.
• Analysis of disulfide bridge positions and sequence variability.
• Comparative sequence analysis with human transferrin.

Main Results:

• 605 out of 705 protein positions were matched between peptide sequences and cDNA-derived sequence.
• The two halves of the ovotransferrin chain exhibit 37% sequence identity.
• 15 disulfide bridges were identified, with 6 homologous pairs in each half and 3 unique to the C-terminal half.
• Sequence variability was observed at 9 positions.

Conclusions:

• Experimental peptide data largely confirm the cDNA-derived sequence of hen ovotransferrin.
• Structural homology exists between the N- and C-terminal halves of the molecule.
• Comparative analysis provides insights into metal-binding residues and transferrin evolution.