Extensive amino acid sequence homologies between animal lectins

Area of Science:

• Biochemistry
• Molecular Biology
• Evolutionary Biology

Background:

• Beta-D-galactoside binding lectins are proteins involved in cell recognition.
• Lectins from various species, including electric eel and human placenta, have been studied for their structure and function.

Purpose of the Study:

• To determine the amino acid sequence of beta-D-galactoside binding lectin from electric eel.
• To compare this sequence with lectins from human placenta, lung, chicken embryo skin, and human hepatomas.
• To investigate evolutionary relationships among beta-D-galactoside binding lectins.

Main Methods:

• Amino acid sequencing of electric eel lectin.
• Peptide sequencing from human placenta lectin.
• Bioinformatic analysis and comparison of published and deduced sequences.
• Hydropathy profile and secondary structure prediction.

Main Results:

• The amino acid sequence of electric eel beta-D-galactoside binding lectin was established.
• Significant sequence homologies were found between electric eel lectin and lectins from human and chicken sources.
• A conserved region likely involved in beta-D-galactoside binding was identified.
• Similar hydropathy profiles and predicted secondary structures suggest conserved protein folding.

Conclusions:

• Beta-D-galactoside binding lectins from diverse species share significant structural homologies.
• These findings strongly suggest that these lectins evolved from a common ancestral gene.
• The conserved regions likely play a crucial role in the lectin's carbohydrate-binding function.