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Domain evolution in the alpha-amylase family
S Janecek1, B Svensson, B Henrissat
1Institute of Microbiology, Slovak Academy of Sciences, Stefánikova 3, SK-81434 Bratislava, Slovakia.
Journal of Molecular Evolution
|September 26, 1997
Summary
Domain B in alpha-amylase enzymes, crucial for specificity, shows varied structures but likely evolved from a common ancestor. Similarities suggest evolutionary links to amino acid transport proteins.
Area of Science:
- Biochemistry
- Structural Biology
- Evolutionary Biology
Background:
- The alpha-amylase family (glycosyl hydrolase family 13) possesses a distinct domain B.
- Domain B protrudes from the catalytic (beta/alpha)8-barrel, located between strand beta3 and helix alpha3.
Purpose of the Study:
- To identify and analyze domain B sequences within the alpha-amylase family.
- To investigate common features and evolutionary relationships of domain B across different enzyme specificities.
Main Methods:
- Searched available amino acid sequences of the alpha-amylase family.
- Performed visual inspection and Hydrophobic Cluster Analysis (HCA) of isolated domain B sequences.
- Analyzed secondary structure variations and compared with known three-dimensional structures.
Main Results:
- Domain B secondary structure varies with enzyme specificity, but likely shares a common evolutionary origin.
- A significant group, structurally similar to Bacillus cereus oligo-1,6-glucosidase domain B, includes various enzymes like alpha-glucosidase and neopullulanase.
- Domain B similarities were also found in mammalian amino acid transport proteins and 4F2 heavy-chain antigens, suggesting evolutionary connections.
Conclusions:
- Domain B's structural diversity points to adaptation for specific enzyme functions.
- Evolutionary links exist between alpha-amylases, amino acid transporters, and cell surface antigens, potentially through domain B.
- The study proposes a possible evolutionary pathway for domain B within the alpha-amylase superfamily.