3REM

Structure of the Isochorismate-Pyruvate Lyase from Pseudomonas aerugionsa with Bound Salicylate and Pyruvate

Summary for 3REM

• Entry DOI: 10.2210/pdb3rem/pdb
• Descriptor: Salicylate biosynthesis protein pchB, 2-HYDROXYBENZOIC ACID, PYRUVIC ACID, ... (4 entities in total)
• Functional Keywords: intertwined dimer, lyase, mutase
• Biological source: Pseudomonas aeruginosa
• Total number of polymer chains: 2
• Total formula weight: 23346.49

Authors

Olucha, J.,Ouellette, A.N.,Luo, Q.,Lamb, A.L. (deposition date: 2011-04-04, release date: 2011-07-27, Last modification date: 2023-11-15)

Primary citation

Olucha, J.,Ouellette, A.N.,Luo, Q.,Lamb, A.L.
pH Dependence of Catalysis by Pseudomonas aeruginosa Isochorismate-Pyruvate Lyase: Implications for Transition State Stabilization and the Role of Lysine 42.
Biochemistry, 50:7198-7207, 2011

PubMed Abstract: An isochorismate-pyruvate lyase with adventitious chorismate mutase activity from Pseudomonas aerugionsa (PchB) achieves catalysis of both pericyclic reactions in part by the stabilization of reactive conformations and in part by electrostatic transition-state stabilization. When the active site loop Lys42 is mutated to histidine, the enzyme develops a pH dependence corresponding to a loss of catalytic power upon deprotonation of the histidine. Structural data indicate that the change is not due to changes in active site architecture, but due to the difference in charge at this key site. With loss of the positive charge on the K42H side chain at high pH, the enzyme retains lyase activity at ∼100-fold lowered catalytic efficiency but loses detectable mutase activity. We propose that both substrate organization and electrostatic transition state stabilization contribute to catalysis. However, the dominant reaction path for catalysis is dependent on reaction conditions, which influence the electrostatic properties of the enzyme active site amino acid side chains.

PubMed: 21751784
DOI: 10.1021/bi200599j

Experimental method

X-RAY DIFFRACTION (1.95 Å)