5FH5: The Structure Of Rat Cytosolic Pepck Variant E89q In Complex With Phosphoglycolate And Gdp

Phosphoenolpyruvate carboxykinase (PEPCK) is an essential metabolic enzyme operating in the gluconeogenesis and glyceroneogenesis pathways. Previous work has demonstrated that the enzyme cycles between a catalytically inactive open state and a catalytically active closed state. The transition of the enzyme between these states requires the transition of several active site loops to shift from mobile, disordered structural elements to stable ordered states. The mechanism by which these disorder-order transitions are coupled to the ligation state of the active site however is not fully understood. To further investigate the mechanisms by which the mobility of the active site loops is coupled to enzymatic function and the transitioning of the enzyme between the two conformational states, we have conducted structural and functional studies of point mutants of E89. E89 is a proposed key member of the interaction network of mobile elements as it resides in the R-loop region of the enzyme active site. These new data demonstrate the importance of the R-loop in coordinating interactions between substrates at the OAA/PEP binding site and the mobile R- and Omega-loop domains. In turn, the studies more generally demonstrate the mechanisms by which the intrinsic ligand binding energy can be utilized in catalysis to drive unfavorable conformational changes, changes that are subsequently required for both optimal catalytic activity and fidelity.
PDB ID: 5FH5Download
MMDB ID: 144676
PDB Deposition Date: 2015/12/21
Updated in MMDB: 2016/11
Experimental Method:
x-ray diffraction
Resolution: 1.55  Å
Source Organism:
Similar Structures:
Biological Unit for 5FH5: monomeric; determined by author and by software (PISA)
Molecular Components in 5FH5
Label Count Molecule
Protein (1 molecule)
Phosphoenolpyruvate Carboxykinase, Cytosolic [gtp](Gene symbol: Pck1)
Molecule annotation
Chemicals (5 molecules)
* Click molecule labels to explore molecular sequence information.

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