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Cho THS, Pick K, Raivio TL. Bacterial envelope stress responses: Essential adaptors and attractive targets. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119387. [PMID: 36336206 DOI: 10.1016/j.bbamcr.2022.119387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 10/05/2022] [Accepted: 10/20/2022] [Indexed: 11/06/2022]
Abstract
Millions of deaths a year across the globe are linked to antimicrobial resistant infections. The need to develop new treatments and repurpose of existing antibiotics grows more pressing as the growing antimicrobial resistance pandemic advances. In this review article, we propose that envelope stress responses, the signaling pathways bacteria use to recognize and adapt to damage to the most vulnerable outer compartments of the microbial cell, are attractive targets. Envelope stress responses (ESRs) support colonization and infection by responding to a plethora of toxic envelope stresses encountered throughout the body; they have been co-opted into virulence networks where they work like global positioning systems to coordinate adhesion, invasion, microbial warfare, and biofilm formation. We highlight progress in the development of therapeutic strategies that target ESR signaling proteins and adaptive networks and posit that further characterization of the molecular mechanisms governing these essential niche adaptation machineries will be important for sparking new therapeutic approaches aimed at short-circuiting bacterial adaptation.
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Affiliation(s)
- Timothy H S Cho
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Kat Pick
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Tracy L Raivio
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
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2
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Park H, Kim S. Gene-specific mutagenesis enables rapid continuous evolution of enzymes in vivo. Nucleic Acids Res 2021; 49:e32. [PMID: 33406230 PMCID: PMC8034631 DOI: 10.1093/nar/gkaa1231] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/02/2020] [Accepted: 12/08/2020] [Indexed: 01/21/2023] Open
Abstract
Various in vivo mutagenesis methods have been developed to facilitate fast and efficient continuous evolution of proteins in cells. However, they either modify the DNA region that does not match the target gene, or suffer from low mutation rates. Here, we report a mutator, eMutaT7 (enhanced MutaT7), with very fast in vivo mutation rate and high gene-specificity in Escherichia coli. eMutaT7, a cytidine deaminase fused to an orthogonal RNA polymerase, can introduce up to ∼4 mutations per 1 kb per day, rivalling the rate in typical in vitro mutagenesis for directed evolution of proteins, and promotes rapid continuous evolution of model proteins for antibiotic resistance and allosteric activation. eMutaT7 provides a very simple and tunable method for continuous directed evolution of proteins, and suggests that the fusion of new DNA-modifying enzymes to the orthogonal RNA polymerase is a promising strategy to explore the expanded sequence space without compromising gene specificity.
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Affiliation(s)
- Hyojin Park
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - Seokhee Kim
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
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Cho H, Choi Y, Min K, Son JB, Park H, Lee HH, Kim S. Over-activation of a nonessential bacterial protease DegP as an antibiotic strategy. Commun Biol 2020; 3:547. [PMID: 33005001 PMCID: PMC7529758 DOI: 10.1038/s42003-020-01266-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 08/25/2020] [Indexed: 11/19/2022] Open
Abstract
Rising antibiotic resistance urgently begs for novel targets and strategies for antibiotic discovery. Here, we report that over-activation of the periplasmic DegP protease, a member of the highly conserved HtrA family, can be a viable strategy for antibiotic development. We demonstrate that tripodal peptidyl compounds that mimic DegP-activating lipoprotein variants allosterically activate DegP and inhibit the growth of an Escherichia coli strain with a permeable outer membrane in a DegP-dependent fashion. Interestingly, these compounds inhibit bacterial growth at a temperature at which DegP is not essential for cell viability, mainly by over-proteolysis of newly synthesized proteins. Co-crystal structures show that the peptidyl arms of the compounds bind to the substrate-binding sites of DegP. Overall, our results represent an intriguing example of killing bacteria by activating a non-essential enzyme, and thus expand the scope of antibiotic targets beyond the traditional essential proteins or pathways. Hyunjin Cho et al. show that peptidyl compounds activating the periplasmic DegP protease inhibit the growth of Escherichia coli by promoting the proteolysis of newly synthesized proteins. This study presents an intriguing strategy to combat antibiotic resistance by activating a non-essential bacterial enzyme, thus expanding the scope of traditional antibiotic targets.
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Affiliation(s)
- Hyunjin Cho
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, South Korea
| | - Yuri Choi
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, South Korea
| | - Kyungjin Min
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, South Korea
| | - Jung Bae Son
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, South Korea
| | - Hyojin Park
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, South Korea
| | - Hyung Ho Lee
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, South Korea
| | - Seokhee Kim
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, South Korea.
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Mycobacterium smegmatis HtrA Blocks the Toxic Activity of a Putative Cell Wall Amidase. Cell Rep 2020; 27:2468-2479.e3. [PMID: 31116989 PMCID: PMC6538288 DOI: 10.1016/j.celrep.2018.12.063] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 10/14/2018] [Accepted: 12/13/2018] [Indexed: 01/14/2023] Open
Abstract
Mycobacterium tuberculosis, the causative agent of tuberculosis, withstands diverse environmental stresses in the host. The periplasmic protease HtrA is required only to survive extreme conditions in most bacteria but is predicted to be essential for normal growth in mycobacteria. We confirm that HtrA is indeed essential in Mycobacterium smegmatis and interacts with another essential protein of unknown function, LppZ. However, the loss of any of three unlinked genes, including those encoding Ami3, a peptidoglycan muramidase, and Pmt, a mannosyltransferase, suppresses the essentiality of both HtrA and LppZ, indicating the functional relevance of these genes' protein products. Our data indicate that HtrA-LppZ is required to counteract the accumulation of active Ami3, which is toxic under the stabilizing influence of Pmt-based mannosylation. This suggests that HtrA-LppZ blocks the toxicity of a cell wall enzyme to maintain mycobacterial homeostasis.
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Merdanovic M, Burston SG, Schmitz AL, Köcher S, Knapp S, Clausen T, Kaiser M, Huber R, Ehrmann M. Activation by substoichiometric inhibition. Proc Natl Acad Sci U S A 2020; 117:1414-1418. [PMID: 31907318 PMCID: PMC6983408 DOI: 10.1073/pnas.1918721117] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Startling reports described the paradoxical triggering of the human mitogen-activated protein kinase pathway when a small-molecule inhibitor specifically inactivates the BRAF V600E protein kinase but not wt-BRAF. We performed a conceptual analysis of the general phenomenon "activation by inhibition" using bacterial and human HtrA proteases as models. Our data suggest a clear explanation that is based on the classic biochemical principles of allostery and cooperativity. Although substoichiometric occupancy of inhibitor binding sites results in partial inhibition, this effect is overrun by a concomitant activation of unliganded binding sites. Therefore, when an inhibitor of a cooperative enzyme does not reach saturating levels, a common scenario during drug administration, it may cause the contrary of the desired effect. The implications for drug development are discussed.
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Affiliation(s)
- Melisa Merdanovic
- Center of Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, 45117 Essen, Germany
| | - Steven G Burston
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, Bristol BS8 1TD, United Kingdom
| | - Anna Laura Schmitz
- Center of Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, 45117 Essen, Germany
| | - Steffen Köcher
- Center of Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, 45117 Essen, Germany
| | - Stefan Knapp
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt, 60438 Frankfurt, Germany
| | - Tim Clausen
- Research Institute of Molecular Pathology, 1030 Vienna, Austria
| | - Markus Kaiser
- Center of Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, 45117 Essen, Germany
| | - Robert Huber
- Center of Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, 45117 Essen, Germany;
- Max-Planck-Institute of Biochemistry, 82152 Martinsried, Germany
| | - Michael Ehrmann
- Center of Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, 45117 Essen, Germany;
- School of Biosciences, Cardiff University, Cardiff CF10 3US, United Kingdom
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