3ZP4

Arg90Cit chorismate mutase of Bacillus subtilis in complex with a transition state analog

Summary for 3ZP4

• Entry DOI: 10.2210/pdb3zp4/pdb
• Related: 3ZO8 3ZOP 3ZP8
• Descriptor: CHORISMATE MUTASE AROH, 8-HYDROXY-2-OXA-BICYCLO[3.3.1]NON-6-ENE-3,5-DICARBOXYLIC ACID (3 entities in total)
• Functional Keywords: pseudo-alpha beta-barrel, isomerase, non-proteinogenic amino acid, semi-synthetic, transition state analog
• Biological source: BACILLUS SUBTILIS
• Cellular location: Cytoplasm : P19080
• Total number of polymer chains: 6
• Total formula weight: 88044.31

Authors

Burschowsky, D.,vanEerde, A.,Okvist, M.,Kienhofer, A.,Kast, P.,Hilvert, D.,Krengel, U. (deposition date: 2013-02-26, release date: 2014-04-16, Last modification date: 2024-11-13)

Primary citation

Burschowsky, D.,Van Eerde, A.,Okvist, M.,Kienhofer, A.,Kast, P.,Hilvert, D.,Krengel, U.
Electrostatic Transition State Stabilization Rather Than Reactant Destabilization Provides the Chemical Basis for Efficient Chorismate Mutase Catalysis.
Proc.Natl.Acad.Sci.USA, 111:17516-, 2014

PubMed Abstract: For more than half a century, transition state theory has provided a useful framework for understanding the origins of enzyme catalysis. As proposed by Pauling, enzymes accelerate chemical reactions by binding transition states tighter than substrates, thereby lowering the activation energy compared with that of the corresponding uncatalyzed process. This paradigm has been challenged for chorismate mutase (CM), a well-characterized metabolic enzyme that catalyzes the rearrangement of chorismate to prephenate. Calculations have predicted the decisive factor in CM catalysis to be ground state destabilization rather than transition state stabilization. Using X-ray crystallography, we show, in contrast, that a sluggish variant of Bacillus subtilis CM, in which a cationic active-site arginine was replaced by a neutral citrulline, is a poor catalyst even though it effectively preorganizes chorismate for the reaction. A series of high-resolution molecular snapshots of the reaction coordinate, including the apo enzyme, and complexes with substrate, transition state analog and product, demonstrate that an active site, which is only complementary in shape to a reactive substrate conformer, is insufficient for effective catalysis. Instead, as with other enzymes, electrostatic stabilization of the CM transition state appears to be crucial for achieving high reaction rates.

PubMed: 25422475
DOI: 10.1073/PNAS.1408512111

Experimental method

X-RAY DIFFRACTION (1.798 Å)