3N4I

Crystal structure of the SHV-1 D104E beta-lactamase/beta-lactamase inhibitor protein (BLIP) complex

Summary for 3N4I

• Entry DOI: 10.2210/pdb3n4i/pdb
• Related: 1JTG 2G2U 3E2L
• Descriptor: Beta-lactamase SHV-1, Beta-lactamase inhibitory protein (3 entities in total)
• Functional Keywords: beta-lactamase, protein-protein complex, blip, shv-1, hydrolase - hydrolase inhibitor complex, hydrolase-hydrolase inhibitor complex, hydrolase/hydrolase inhibitor
• Biological source: Klebsiella pneumoniae; More
• Cellular location: Secreted: P35804
• Total number of polymer chains: 2
• Total formula weight: 46477.54

Authors

Hanes, M.S.,Reynolds, K.A.,McNamara, C.,Ghosh, P.,Bonomo, R.A.,Kirsch, J.F.,Handel, T.M. (deposition date: 2010-05-21, release date: 2011-03-09, Last modification date: 2023-09-06)

Primary citation

Hanes, M.S.,Reynolds, K.A.,McNamara, C.,Ghosh, P.,Bonomo, R.A.,Kirsch, J.F.,Handel, T.M.
Specificity and Cooperativity at beta-lactamase Position 104 in TEM-1/BLIP and SHV-1/BLIP interactions
Proteins, 79:1267-1276, 2011

PubMed Abstract: Establishing a quantitative understanding of the determinants of affinity in protein-protein interactions remains challenging. For example, TEM-1/β-lactamase inhibitor protein (BLIP) and SHV-1/BLIP are homologous β-lactamase/β-lactamase inhibitor protein complexes with disparate K(d) values (3 nM and 2 μM, respectively), and a single substitution, D104E in SHV-1, results in a 1000-fold enhancement in binding affinity. In TEM-1, E104 participates in a salt bridge with BLIP K74, whereas the corresponding SHV-1 D104 does not in the wild type SHV-1/BLIP co-structure. Here, we present a 1.6 Å crystal structure of the SHV-1 D104E/BLIP complex that demonstrates that this point mutation restores this salt bridge. Additionally, mutation of a neighboring residue, BLIP E73M, results in salt bridge formation between SHV-1 D104 and BLIP K74 and a 400-fold increase in binding affinity. To understand how this salt bridge contributes to complex affinity, the cooperativity between the E/K or D/K salt bridge pair and a neighboring hot spot residue (BLIP F142) was investigated using double mutant cycle analyses in the background of the E73M mutation. We find that BLIP F142 cooperatively stabilizes both interactions, illustrating how a single mutation at a hot spot position can drive large perturbations in interface stability and specificity through a cooperative interaction network.

PubMed: 21294157
DOI: 10.1002/prot.22961

Experimental method

X-RAY DIFFRACTION (1.56 Å)