3C7U

Structural Insight into the Kinetics and Cp of interactions between TEM-1-Lactamase and BLIP

Summary for 3C7U

• Entry DOI: 10.2210/pdb3c7u/pdb
• Related: 1jtg 3C7V
• Descriptor: Beta-lactamase, Beta-lactamase inhibitory protein (3 entities in total)
• Functional Keywords: enzyme-inhibitor complex, antibiotic resistance, hydrolase, plasmid, secreted, hydrolase-hydrolase inhibitor complex, hydrolase/hydrolase inhibitor
• Biological source: Escherichia coli; More
• Cellular location: Secreted: P35804
• Total number of polymer chains: 4
• Total formula weight: 92850.87

Authors

Wang, J.,Chow, D.-C. (deposition date: 2008-02-08, release date: 2008-10-07, Last modification date: 2024-11-13)

Primary citation

Wang, J.,Palzkill, T.,Chow, D.C.
Structural insight into the kinetics and DeltaCp of interactions between TEM-1 beta-lactamase and beta-lactamase inhibitory protein (BLIP)
J.Biol.Chem., 284:595-609, 2009

PubMed Abstract: In a previous study, we examined thermodynamic parameters for 20 alanine mutants in beta-lactamase inhibitory protein (BLIP) for binding to TEM-1 beta-lactamase. Here we have determined the structures of two thermodynamically distinctive complexes of BLIP mutants with TEM-1 beta-lactamase. The complex BLIP Y51A-TEM-1 is a tight binding complex with the most negative binding heat capacity change (DeltaG = approximately -13 kcal mol(-1) and DeltaCp = approximately -0.8 kcal mol(-1) K(-1)) among all of the mutants, whereas BLIP W150A-TEM-1 is a weak complex with one of the least negative binding heat capacity changes (DeltaG = approximately -8.5 kcal mol(-1) and DeltaCp = approximately -0.27 kcal mol(-1) K(-1)). We previously determined that BLIP Tyr51 is a canonical and Trp150 an anti-canonical TEM-1-contact residue, where canonical refers to the alanine substitution resulting in a matched change in the hydrophobicity of binding free energy. Structure determination indicates a rearrangement of the interactions between Asp49 of the W150A BLIP mutant and the catalytic pocket of TEM-1. The Asp49 of W150A moves more than 4 angstroms to form two new hydrogen bonds while losing four original hydrogen bonds. This explains the anti-canonical nature of the Trp150 to alanine substitution, and also reveals a strong long distance coupling between Trp150 and Asp49 of BLIP, because these two residues are more than 25 angstroms apart. Kinetic measurements indicate that the mutations influence the dissociation rate but not the association rate. Further analysis of the structures indicates that an increased number of interface-trapped water molecules correlate with poor interface packing in a mutant. It appears that the increase of interface-trapped water molecules is inversely correlated with negative binding heat capacity changes.

PubMed: 18840610
DOI: 10.1074/jbc.M804089200

Experimental method

X-RAY DIFFRACTION (2.2 Å)