3ZHH

X-ray structure of the full-length beta-lactamase from M.tuberculosis

Summary for 3ZHH

• Entry DOI: 10.2210/pdb3zhh/pdb
• Descriptor: BETA-LACTAMASE, SULFATE ION (3 entities in total)
• Functional Keywords: hydrolase
• Biological source: MYCOBACTERIUM TUBERCULOSIS
• Cellular location: Cell membrane; Lipid-anchor (Potential): P0C5C1
• Total number of polymer chains: 4
• Total formula weight: 118820.54

Authors

Feiler, C.,Fisher, A.C.,Marrichi, M.J.,Wright, L.,Schmidpeter, P.A.M.,Blankenfeldt, W.,Pavelka, M.,DeLisa, M.P. (deposition date: 2012-12-21, release date: 2013-09-25, Last modification date: 2023-12-20)

Primary citation

Feiler, C.,Fisher, A.C.,Boock, J.T.,Marrichi, M.J.,Wright, L.,Schmidpeter, P.A.M.,Blankenfeldt, W.,Pavelka, M.,Delisa, M.P.
Directed Evolution of Mycobacterium Tuberculosis Beta-Lactamase Reveals Gatekeeper Residue that Regulates Antibiotic Resistance and Catalytic Efficiency.
Plos One, 8:73123-, 2013

PubMed Abstract: Directed evolution can be a powerful tool for revealing the mutational pathways that lead to more resistant bacterial strains. In this study, we focused on the bacterium Mycobacterium tuberculosis, which is resistant to members of the β-lactam class of antibiotics and thus continues to pose a major public health threat. Resistance of this organism is the result of a chromosomally encoded, extended spectrum class A β-lactamase, BlaC, that is constitutively produced. Here, combinatorial enzyme libraries were selected on ampicillin to identify mutations that increased resistance of bacteria to β-lactams. After just a single round of mutagenesis and selection, BlaC mutants were evolved that conferred 5-fold greater antibiotic resistance to cells and enhanced the catalytic efficiency of BlaC by 3-fold compared to the wild-type enzyme. All isolated mutants carried a mutation at position 105 (e.g., I105F) that appears to widen access to the active site by 3.6 Å while also stabilizing the reorganized topology. In light of these findings, we propose that I105 is a 'gatekeeper' residue of the active site that regulates substrate hydrolysis by BlaC. Moreover, our results suggest that directed evolution can provide insight into the development of highly drug resistant microorganisms.

PubMed: 24023821
DOI: 10.1371/JOURNAL.PONE.0073123

Experimental method

X-RAY DIFFRACTION (2.85 Å)