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Biochemistry, Biophysics, and Structural Biology Commons

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Retrospective Theses and Dissertations

Physical Sciences and Mathematics

Biophysics

1998

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Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

X-Ray Crystallographic Studies On Adenylosuccinate Synthetase From Escherichia Coli , Zhenglin Hou Jan 1998

X-Ray Crystallographic Studies On Adenylosuccinate Synthetase From Escherichia Coli , Zhenglin Hou

Retrospective Theses and Dissertations

Adenylosuccinate synthetase catalyzes the first committed step in de novo biosyntheses of AMP from IMP and aspartate, using GTP as the energy source. Metal cations, ligand-induced conformational transitions and metabolic effectors significantly influence the catalytic potential of the synthetase. The Mg2+, Mn2+, or Ca 2+ bind to the same site, coordinating alpha-, beta-, and gamma-phosphoryl groups of GTP. The level of catalysis supported by each cation is linked to its influence on the basicity of Asp13, a residue which abstracts the proton from N1 of IMP. Zn2+, a potent inhibitor of the synthetase, coordinates the beta- and gamma-phosphoryl groups of ...