Mutations in the Conserved Glycine and Serine of the MutS ABC signature motif affect Nucleotide Exchange, Kinetics of sliding clamp release of mismatch and mismatch repair

Acharya, Samir; Patterson, Kara

doi:10.1016/j.mrfmmm.2009.11.007

Cited by 7 publications

(8 citation statements)

References 37 publications

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“…3) that is critically required for its function. R656 is a part of the "palm" region within the AAA family ATPase domain and is immediately adjacent to the strongly conserved MutS "signature" motif (48). Mutations within this same domain in the human MutS homologue underlie the hypermutation phenotype and microsatellite instability seen in hereditary nonpolyposis colorectal cancer (49,50).…”

Section: Resultsmentioning

confidence: 99%

Dynamic Emergence of Mismatch Repair Deficiency Facilitates Rapid Evolution of Ceftazidime-Avibactam Resistance in Pseudomonas aeruginosa Acute Infection

Khil

Chiang

et al. 2019

mBio

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Strains of Pseudomonas aeruginosa with deficiencies in DNA mismatch repair have been studied in the context of chronic infection, where elevated mutational rates (“hypermutation”) may facilitate the acquisition of antimicrobial resistance. Whether P. aeruginosa hypermutation can also play an adaptive role in the more dynamic context of acute infection remains unclear. In this work, we demonstrate that evolved mismatch repair deficiencies may be exploited by P. aeruginosa to facilitate rapid acquisition of antimicrobial resistance in acute infection, and we directly document rapid clonal succession by such a hypermutating lineage in a patient. Whole-genome sequencing (WGS) was performed on nine serially cultured blood and respiratory isolates from a patient in whom ceftazidime-avibactam (CZA) resistance emerged in vivo over the course of days. The CZA-resistant clone was differentiated by 14 mutations, including a gain-of-function G183D substitution in the PDC-5 chromosomal AmpC cephalosporinase conferring CZA resistance. This lineage also contained a substitution (R656H) at a conserved position in the ATPase domain of the MutS mismatch repair (MMR) protein, and elevated mutational rates were confirmed by mutational accumulation experiments with WGS of evolved lineages in conjunction with rifampin resistance assays. To test whether MMR-deficient hypermutation could facilitate rapid acquisition of CZA resistance, in vitro adaptive evolution experiments were performed with a mutS-deficient strain. These experiments demonstrated rapid hypermutation-facilitated acquisition of CZA resistance compared with the isogenic wild-type strain. Our results suggest a possibly underappreciated role for evolved MMR deficiency in facilitating rapid adaptive evolution of P. aeruginosa in the context of acute infection. IMPORTANCE Antimicrobial resistance in bacteria represents one of the most consequential problems in modern medicine, and its emergence and spread threaten to compromise central advances in the treatment of infectious diseases. Ceftazidime-avibactam (CZA) belongs to a new class of broad-spectrum beta-lactam/beta-lactamase inhibitor combinations designed to treat infections caused by multidrug-resistant bacteria. Understanding the emergence of resistance to this important new drug class is of critical importance. In this work, we demonstrate that evolved mismatch repair deficiency in P. aeruginosa, an important pathogen responsible for significant morbidity and mortality among hospitalized patients, may facilitate rapid acquisition of resistance to CZA in the context of acute infection. These findings are relevant for both diagnosis and treatment of antimicrobial resistance emerging in acute infection in the hypermutator background and additionally have implications for the emergence of more virulent phenotypes.

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Section: Resultsmentioning

confidence: 99%

Dynamic Emergence of Mismatch Repair Deficiency Facilitates Rapid Evolution of Ceftazidime-Avibactam Resistance in Pseudomonas aeruginosa Acute Infection

Khil

Chiang

et al. 2019

mBio

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“…An E. coli mutant carrying the mutS-F36A mutation is deficient in MMC (41), but the mutant protein can still bind to a G4 structure in vitro, at 70% of the wild-type level (36). In addition, mutation of the conserved E. coli mutS serine 668 to alanine (S668A) in the ATPase domain results in a mutant MutS with parental levels of DNA binding to mismatches (and presumably G4s) but is unable to perform MMC (43). The corresponding mutS-F32A and -S661A site-directed mutations were independently constructed and introduced into the mutS locus in N. gonorrhoeae FA1090 ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Neisseria gonorrhoeae MutS Affects Pilin Antigenic Variation through Mismatch Correction and Not by pilE Guanine Quartet Binding

Rotman

Seifert

2015

J Bacteriol

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Many pathogens use homologous recombination to vary surface antigens to avoid immune surveillance. Neisseria gonorrhoeae achieves this in part by changing the properties of its surface pili in a process called pilin antigenic variation (AV). Pilin AV occurs by high-frequency gene conversion reactions that transfer silent pilS sequences into the expressed pilE locus and requires the formation of an upstream guanine quartet (G4) DNA structure to initiate this process. The MutS and MutL proteins of the mismatch correction (MMC) system act to correct mismatches after replication and prevent homeologous (i.e., partially homologous) recombination, but MutS orthologs can also bind to G4 structures. A previous study showed that mutation of MutS resulted in a 3-fold increase in pilin AV, which could be due to the loss of MutS antirecombination properties or loss of G4 binding. We tested two site-directed separation-of-function MutS mutants that are both predicted to bind to G4s but are not able to perform MMC. Pilus phase variation assays and DNA sequence analysis of pilE variants produced in these mutants showed that all three mutS mutants and a mutL mutant had similar increased frequencies of pilin AV. Moreover, the mutS mutants all showed similar increased levels of pilin AV-dependent synthetic lethality. These results show that antirecombination by MMC is the reason for the effect that MutS has on pilin AV and is not due to pilE G4 binding by MutS. IMPORTANCENeisseria gonorrhoeae continually changes its outer surface proteins to avoid recognition by the immune system. N. gonorrhoeae alters the antigenicity of the pilus by directed recombination between partially homologous pilin copies in a process that requires a guanine quartet (G4) structure. The MutS protein of the mismatch correction (MMC) system prevents recombination between partially homologous sequences and can also bind to G4s. We confirmed that loss of MMC increases the frequency of pilin antigenic variation and that two MutS mutants that are predicted to separate the two different functions of MutS inhibit pilin variation similarly to a complete-loss-of-function mutant, suggesting that interaction of MutS with the G4 structure is not a major factor in this process. N eisseria gonorrhoeae is the sole causative agent of gonorrhea, the second most commonly reported sexually transmitted infection in the United States, with an estimated 800,000 new cases per year (1). N. gonorrhoeae extensively uses phase and antigenic variation to provide a reversible subpopulation of genetic variants that can be selected for during infection (2). The use of various surface antigens is one of the most effective strategies used by pathogens to evade immune surveillance. By changing outer surface components, N. gonorrhoeae can avoid recognition by the adaptive immune system, which can prolong a current infection and enable reinfection. These diversity generation mechanisms can also provide functional changes for N. gonorrhoeae.It is estimated that there are over 100 pha...

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“…More precisely, the signature motif binds the ATP γ‐phosphate via the conserved serine and second glycine, providing a mechanism how hydrolysis of ATP to ADP leads to separation of the tight NBD dimer. Mutations in the signature motif that prevent NBD dimer engagement typically inactivate ABC proteins …”

Section: Nbd Dimer Structure and Mechanism Of Ntp Hydrolysismentioning

confidence: 99%

Invited review: Architectures and mechanisms of ATP binding cassette proteins

Hopfner

2016

Biopolymers

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ATP binding cassette (ABC) ATPases form chemo-mechanical engines and switches that function in a broad range of biological processes. Most prominently, a very large family of integral membrane NTPases -ABC transporters -catalyzes the import or of a diverse molecules across membranes. ABC proteins are also critical components of the chromosome segregation, recombination and DNA repair machineries and regulate or catalyze critical steps of ribosomal protein synthesis. Recent structural and mechanistic studies draw interesting architectural and mechanistic parallels between diverse ABC proteins. Here I review the current state of our understanding how NTP-dependent conformational changes of ABC proteins drive diverse biological processes.

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Mutations in the Conserved Glycine and Serine of the MutS ABC signature motif affect Nucleotide Exchange, Kinetics of sliding clamp release of mismatch and mismatch repair

Cited by 7 publications

References 37 publications

Dynamic Emergence of Mismatch Repair Deficiency Facilitates Rapid Evolution of Ceftazidime-Avibactam Resistance in Pseudomonas aeruginosa Acute Infection

Dynamic Emergence of Mismatch Repair Deficiency Facilitates Rapid Evolution of Ceftazidime-Avibactam Resistance in Pseudomonas aeruginosa Acute Infection

Neisseria gonorrhoeae MutS Affects Pilin Antigenic Variation through Mismatch Correction and Not by pilE Guanine Quartet Binding

Invited review: Architectures and mechanisms of ATP binding cassette proteins

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