Electric eel acetylcholinesterase: a multisubunit enzyme containing a collagen tail
Monographs in Neural Sciences
|January 1, 1980
Summary
The fibrous tail of acetylcholinesterase (AChE) is a collagen triple helix, crucial for anchoring the enzyme. This structure enables AChE aggregation, potentially linking it to the basal lamina matrix.
Area of Science:
- Biochemistry
- Molecular Biology
- Neuroscience
Background:
- Acetylcholinesterase (AChE) exists in various molecular forms in electric organ tissue.
- The predominant 18S AChE form is a large, elongated structure with a catalytic head and a fibrous tail.
- This 18S form exhibits reversible aggregation at low ionic strength.
Purpose of the Study:
- To elucidate the molecular composition and function of the fibrous tail of elongated AChE forms.
- To investigate the role of the tail in AChE aggregation and its potential interaction with the extracellular matrix.
Main Methods:
- Enzymatic digestion (trypsin, collagenase, pepsin) of AChE.
- Amino acid analysis.
- Immunological techniques.
- Analysis of AChE aggregation properties at varying ionic strengths.
Main Results:
- The fibrous tail of AChE was identified as a collagen triple helix.
- Trypsin digestion removed the tail, converting 18S AChE into a non-aggregating 11S globular tetramer.
- A specific region in the distal part of the tail mediates low ionic strength aggregation.
Conclusions:
- The fibrous tail of AChE is composed of collagen, contributing to its elongated structure.
- The tail's collagenous nature and specific distal region are essential for AChE's aggregation properties.
- These findings support the hypothesis that the tail anchors AChE to the basal lamina, influencing enzyme localization and function.
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