2xh4

Engineering the enolase active site pocket: Crystal structure of the S39A D321A mutant of yeast enolase 1

spinqualitylabelsall models 2xh4, resolution 1.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2xh4 is a 4 chain structure with sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.7Å Ligands: 2PG, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ENO1_YEAST Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The glycolytic enzyme enolase catalyzes the reversible elimination of water from 2-phosphoglycerate (2-PGA) to form phosphoenolpyruvate (PEP). Two magnesium ions in the active site are thought to facilitate the reaction by activation of the C2 proton of 2-PGA and charge stabilization of the intermediate. The initial abstraction of a proton from a carboxylic acid is common to all members of the enolase superfamily, yet in all other known members of this superfamily, only one magnesium ion (MgI) per active site is sufficient to promote catalysis. We wanted to further investigate the importance of the second magnesium ion (MgII) for the catalytic mechanism of yeast enolase 1. Toward this end, we removed all MgII coordinating residues and replaced substrate-MgII interactions by introducing positively charged side chains. High-resolution crystal structures and activity assays show that the introduced positively charged side chains effectively prohibit MgII binding but fail to promote catalysis. We conclude that enolase is inactive without MgII, yet control mutants without additional positively charged side chains retain basal enolase activity through binding of magnesium to 2-PGA in an open active site without the help of MgII coordinating residues. Thus, we believe that ancestral enolase activity might have evolved in a member of the enolase superfamily that provides only the necessary catalytic residues and the binding site for MgI. Additionally, precatalytic binding of 2-PGA to the apo state of enolase was observed. Engineering the Enolase Magnesium II Binding Site: Implications for Its Evolution.,Schreier B, Hocker B Biochemistry. 2010 Aug 17. PMID:20690637 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Enolase 3D structures

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