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Theses/Dissertations

Genetics

1996

Genetics

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Full-Text Articles in Molecular Biology

Genetic Construction And Biochemical Analysis Of Thermostability Mutants Of Glucoamylase From Aspergillus Awamori , Yuxing Li Jan 1996

Genetic Construction And Biochemical Analysis Of Thermostability Mutants Of Glucoamylase From Aspergillus Awamori , Yuxing Li

Retrospective Theses and Dissertations

To study the molecular basis of Aspergillus awamori glucoamylase (GA) thermostability, eighteen mutants were constructed by site-directed mutagenesis and expressed in Saccharomyces cerevisiae based on thermostability theories. Four lysine residues, K61, K279, K352 and K404, were replaced with arginine, with all but K404 well exposed to the solvent and far away from the enzyme activity site. Mutations K61F/D65E and H254W/E326Q were made to fill a packing void around the inner set of six [alpha]-helices of GA and to displace water molecules inside the void. Five residues (A27, A393, A435, Ser436 and Ser460) were replaced with proline. Two ...