# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 6006 | 0 | 0.9896 | Missense Mutations in the CrrB Protein Mediate Odilorhabdin Derivative Resistance in Klebsiella pneumoniae. NOSO-502 is a preclinical antibiotic candidate of the Odilorhabdin class. This compound exhibits activity against Enterobacteriaceae pathogens, including carbapenemase-producing bacteria and most of the Colistin (CST)-resistant strains. Among a collection of CST-resistant Klebsiella pneumoniae strains harboring mutations on genes pmrAB, mgrB, phoPQ, and crrB, only those bearing mutations in gene crrB were found to be resistant to NOSO-502.CrrB is a histidine kinase which acts with the response regulator CrrA to modulate the PmrAB system, which finally induces the restructuring of the lipopolysaccharide present on the outer membrane and thus leading to CST resistance. Moreover, crrB mutations also enhance the transcription of neighboring genes such as H239_3063, an ABC transporter transmembrane region; H239_3064, a putative efflux pump also known as KexD; and H239_3065, a N-acetyltransferase.To elucidate the mechanism of resistance to NOSO-502 induced by CrrB missense mutations in K. pneumoniae, mutants of NCTC 13442 and ATCC BAA-2146 strains resistant to NOSO-502 and CST with single amino acid substitutions in CrrB (S8N, F33Y, Y34N, W140R, N141I, P151A, P151L, P151S, P151T, F303Y) were selected. Full susceptibility to NOSO-502 was restored in crrA or crrB deleted K. pneumoniae NCTC 13442 CrrB(P151L) mutants, confirming the role of CrrAB in controlling this resistance pathway. Deletion of kexD (but no other neighboring genes) in the same mutant also restored NOSO-502-susceptibility. Upregulation of the kexD gene expression was observed for all CrrB mutants. Finally, plasmid expression of kexD in a K. pneumoniae strain missing the locus crrABC and kexD significantly increased resistance to NOSO-502. | 2023 | 33685902 |
| 181 | 1 | 0.9891 | Cytoplasmic CopZ-Like Protein and Periplasmic Rusticyanin and AcoP Proteins as Possible Copper Resistance Determinants in Acidithiobacillus ferrooxidans ATCC 23270. Acidophilic organisms, such as Acidithiobacillus ferrooxidans, possess high-level resistance to copper and other metals. A. ferrooxidans contains canonical copper resistance determinants present in other bacteria, such as CopA ATPases and RND efflux pumps, but these components do not entirely explain its high metal tolerance. The aim of this study was to find other possible copper resistance determinants in this bacterium. Transcriptional expression of A. ferrooxidans genes coding for a cytoplasmic CopZ-like copper-binding chaperone and the periplasmic copper-binding proteins rusticyanin and AcoP, which form part of an iron-oxidizing supercomplex, was found to increase when the microorganism was grown in the presence of copper. All of these proteins conferred more resistance to copper when expressed heterologously in a copper-sensitive Escherichia coli strain. This effect was absent when site-directed-mutation mutants of these proteins with altered copper-binding sites were used in this metal sensitivity assay. These results strongly suggest that the three copper-binding proteins analyzed here are copper resistance determinants in this extremophile and contribute to the high-level metal resistance of this industrially important biomining bacterium. | 2016 | 26637599 |
| 128 | 2 | 0.9889 | Identification of a novel system for boron transport: Atr1 is a main boron exporter in yeast. Boron is a micronutrient in plants and animals, but its specific roles in cellular processes are not known. To understand boron transport and functions, we screened a yeast genomic DNA library for genes that confer resistance to the element in Saccharomyces cerevisiae. Thirty boron-resistant transformants were isolated, and they all contained the ATR1 (YML116w) gene. Atr1 is a multidrug resistance transport protein belonging to the major facilitator superfamily. C-terminal green fluorescent protein-tagged Atr1 localized to the cell membrane and vacuole, and ATR1 gene expression was upregulated by boron and several stress conditions. We found that atr1Delta mutants were highly sensitive to boron treatment, whereas cells overexpressing ATR1 were boron resistant. In addition, atr1Delta cells accumulated boron, whereas ATR1-overexpressing cells had low intracellular levels of the element. Furthermore, atr1Delta cells showed stronger boron-dependent phenotypes than mutants deficient in genes previously reported to be implicated in boron metabolism. ATR1 is widely distributed in bacteria, archaea, and lower eukaryotes. Our data suggest that Atr1 functions as a boron efflux pump and is required for boron tolerance. | 2009 | 19414602 |
| 556 | 3 | 0.9888 | An ArsR/SmtB family member regulates arsenic resistance genes unusually arranged in Thermus thermophilus HB27. Arsenic resistance is commonly clustered in ars operons in bacteria; main ars operon components encode an arsenate reductase, a membrane extrusion protein, and an As-sensitive transcription factor. In the As-resistant thermophile Thermus thermophilus HB27, genes encoding homologues of these proteins are interspersed in the chromosome. In this article, we show that two adjacent genes, TtsmtB, encoding an ArsR/SmtB transcriptional repressor and, TTC0354, encoding a Zn(2+) /Cd(2+) -dependent membrane ATPase are involved in As resistance; differently from characterized ars operons, the two genes are transcribed from dedicated promoters upstream of their respective genes, whose expression is differentially regulated at transcriptional level. Mutants defective in TtsmtB or TTC0354 are more sensitive to As than the wild type, proving their role in arsenic resistance. Recombinant dimeric TtSmtB binds in vitro to both promoters, but its binding capability decreases upon interaction with arsenate and, less efficiently, with arsenite. In vivo and in vitro experiments also demonstrate that the arsenate reductase (TtArsC) is subjected to regulation by TtSmtB. We propose a model for the regulation of As resistance in T. thermophilus in which TtSmtB is the arsenate sensor responsible for the induction of TtArsC which generates arsenite exported by TTC0354 efflux protein to detoxify cells. | 2017 | 28696001 |
| 6221 | 4 | 0.9888 | Characterization of the Tellurite-Resistance Properties and Identification of the Core Function Genes for Tellurite Resistance in Pseudomonas citronellolis SJTE-3. Tellurite is highly toxic to bacteria and commonly used in the clinical screening for pathogens; it is speculated that there is a potential relationship between tellurite resistance and bacterial pathogenicity. Until now, the core function genes of tellurite resistance and their characteristics are still obscure. Pseudomonas citronellolis SJTE-3 was found able to resist high concentrations of tellurite (250 μg/mL) and formed vacuole-like tellurium nanostructures. The terZABCDE gene cluster located in the large plasmid pRBL16 endowed strain SJTE-3 with the tellurite resistance of high levels. Although the terC and terD genes were identified as the core function genes for tellurite reduction and resistance, the inhibition of cell growth was observed when they were used solely. Interestingly, co-expression of the terA gene or terZ gene could relieve the burden caused by the expression of the terCD genes and recover normal cell growth. TerC and TerD proteins commonly shared the conserved sequences and are widely distributed in many pathogenic bacteria, highly associated with the pathogenicity factors. | 2022 | 35056544 |
| 395 | 5 | 0.9887 | O-antigen protects gram-negative bacteria from histone killing. Beyond their traditional role of wrapping DNA, histones display antibacterial activity to Gram-negative and -positive bacteria. To identify bacterial components that allow survival to a histone challenge, we selected resistant bacteria from homologous Escherichia coli libraries that harbor plasmids carrying pieces of the chromosome in different sizes. We identified genes required for exopolysaccharide production and for the synthesis of the polysaccharide domain of the lipopolysaccharide, called O-antigen. Indeed, O-antigen and exopolysaccharide conferred further resistance to histones. Notably, O-antigen also conferred resistance to histones in the pathogens Shigella flexneri and Klebsiella pneumoniae. | 2013 | 23951089 |
| 507 | 6 | 0.9886 | Tellurite resistance and reduction by obligately aerobic photosynthetic bacteria. Seven species of obligately aerobic photosynthetic bacteria of the genera Erythromicrobium, Erythrobacter, and Roseococcus demonstrated high-level resistance to tellurite and accumulation of metallic tellurium crystals. High-level resistance without tellurite reduction was observed for Roseococcus thiosulfatophilus and Erythromicrobium ezovicum grown with certain organic carbon sources, implying that tellurite reduction is not essential to confer tellurite resistance. | 1996 | 16535446 |
| 640 | 7 | 0.9886 | cor, a novel carbon monoxide resistance gene, is essential for Mycobacterium tuberculosis pathogenesis. Tuberculosis, caused by Mycobacterium tuberculosis, remains a devastating human infectious disease, causing two million deaths annually. We previously demonstrated that M. tuberculosis induces an enzyme, heme oxygenase (HO1), that produces carbon monoxide (CO) gas and that M. tuberculosis adapts its transcriptome during CO exposure. We now demonstrate that M. tuberculosis carries a novel resistance gene to combat CO toxicity. We screened an M. tuberculosis transposon library for CO-susceptible mutants and found that disruption of Rv1829 (carbon monoxide resistance, Cor) leads to marked CO sensitivity. Heterologous expression of Cor in Escherichia coli rescued it from CO toxicity. Importantly, the virulence of the cor mutant is attenuated in a mouse model of tuberculosis. Thus, Cor is necessary and sufficient to protect bacteria from host-derived CO. Taken together, this represents the first report of a role for HO1-derived CO in controlling infection of an intracellular pathogen and the first identification of a CO resistance gene in a pathogenic organism. IMPORTANCE: Macrophages produce a variety of antimicrobial molecules, including nitric oxide (NO), hydrogen peroxide (H2O2), and acid (H+), that serve to kill engulfed bacteria. In addition to these molecules, human and mouse macrophages also produce carbon monoxide (CO) gas by the heme oxygenase (HO1) enzyme. We observed that, in contrast to other bacteria, mycobacteria are resistant to CO, suggesting that this might be an evolutionary adaptation of mycobacteria for survival within macrophages. We screened a panel of ~2,500 M. tuberculosis mutants to determine which genes are required for survival of M. tuberculosis in the presence of CO. Within this panel, we identified one such gene, cor, that specifically confers CO resistance. Importantly, we found that the ability of M. tuberculosis cells carrying a mutated copy of this gene to cause tuberculosis in a mouse disease model is significantly attenuated. This indicates that CO resistance is essential for mycobacterial survival in vivo. | 2013 | 24255121 |
| 6178 | 8 | 0.9885 | Involvement of MarR and YedS in carbapenem resistance in a clinical isolate of Escherichia coli from China. A carbapenem-resistant clinical isolate of Escherichia coli, which lacked OmpF and OmpC porins, carried a marR mutation and expressed a functional yedS, a normally nontranslated gene. MarR and YedS are described here as having effects on the ability of this strain to resist carbapenems. Additionally, expression of YedS was regulated by the small RNA MicF in a MarA-dependent way. These findings illustrate how broadly bacteria can mutate within a selective clinical setting, in this case, resistance to carbapenems, by altering three porin genes and one regulatory gene. | 2013 | 23318808 |
| 367 | 9 | 0.9885 | Translocatable resistance to mercuric and phenylmercuric ions in soil bacteria. Of a sample of 42 gram-negative Hg-resistant bacteria, three (a Pseudomonas fluorescens, a Klebsiella sp. and a Citrobacter sp.) contained translocatable elements conferring resistance to Hg2+ (all three) and to Hg2+ and phenylmercuric acetate (P. fluorescens). The discovery of transposable phenylmercuric acetate resistance extends the range of known resistance "transposons" from heavy metals and antibiotics to organometallic compounds. | 1981 | 6268601 |
| 579 | 10 | 0.9885 | Control of expression of a periplasmic nickel efflux pump by periplasmic nickel concentrations. There is accumulating evidence that transenvelope efflux pumps of the resistance, nodulation, cell division protein family (RND) are excreting toxic substances from the periplasm across the outer membrane directly to the outside. This would mean that resistance of Gram-negative bacteria to organic toxins and heavy metals is in fact a two-step process: one set of resistance factors control the concentration of a toxic substance in the periplasm, another one that in the cytoplasm. Efficient periplasmic detoxification requires periplasmic toxin sensing and transduction of this signal into the cytoplasm to control expression of the periplasmic detoxification system. Such a signal transduction system was analyzed using the Cnr nickel resistance system from Cupriavidus (Wautersia, Ralstonia, Alcaligenes) metallidurans strain CH34. Resistance is based on nickel efflux mediated by the CnrCBA efflux pump encoded by the cnrYHXCBAT metal resistance determinant. The products of the three genes cnrYXH transcriptionally regulate expression of cnr. CnrY and CnrX are membrane-bound proteins probably functioning as anti sigma factors while CnrH is a cnr-specific extracytoplasmic functions (ECF) sigma factors. Experimental data provided here indicate a signal transduction chain leading from nickel in the periplasm to transcription initiation at the cnr promoters cnrYp and cnrCp, which control synthesis of the nickel efflux pump CnrCBA. | 2005 | 16158236 |
| 122 | 11 | 0.9884 | Functional characterization of ORCTL2--an organic cation transporter expressed in the renal proximal tubules. Chromosome 11p15.5 harbors a gene or genes involved in Beckwith-Wiedemann syndrome that confer(s) susceptibility to Wilms' tumor, rhabdomyosarcoma, and hepatoblastoma. We have previously identified a transcript at 11p15.5 which encodes a putative membrane transport protein, designated organic cation transporter-like 2 (ORCTL2), that shares homology with tetracycline resistance proteins and bacterial multidrug resistance proteins. In this report, we have investigated the transport properties of ORCTL2 and show that this protein can confer resistance to chloroquine and quinidine when overexpressed in bacteria. Immunohistochemistry analyses performed with anti-ORCTL2 polyclonal antibodies on human renal sections indicate that ORCTL2 is localized on the apical membrane surface of the proximal tubules. These results suggest that ORCTL2 may play a role in the transport of chloroquine and quinidine related compounds in the kidney. | 1998 | 9744804 |
| 688 | 12 | 0.9883 | The cop operon is required for copper homeostasis and contributes to virulence in Streptococcus pneumoniae. High levels of copper are toxic and therefore bacteria must limit free intracellular levels to prevent cellular damage. In this study, we show that a number of pneumococcal genes are differentially regulated by copper, including an operon encoding a CopY regulator, a protein of unknown function (CupA) and a P1-type ATPase, CopA, which is conserved in all sequenced Streptococcus pneumoniae strains. Transcriptional analysis demonstrated that the cop operon is induced by copper in vitro, repressed by the addition of zinc and is autoregulated by the copper-responsive CopY repressor protein. We also demonstrate that the CopA ATPase is a major pneumococcal copper resistance mechanism and provide the first evidence that the CupA protein plays a role in copper resistance. Our results also show that copper homeostasis is important for pneumococcal virulence as the expression of the cop operon is induced in the lungs and nasopharynx of intranasally infected mice, and a copA(-) mutant strain, which had decreased growth in high levels of copper in vitro, showed reduced virulence in a mouse model of pneumococcal pneumonia. Furthermore, using the copA(-) mutant we observed for the first time in any bacteria that copper homeostasis also appears to be required for survival in the nasopharynx. | 2011 | 21736642 |
| 6231 | 13 | 0.9883 | NMR structure and calcium-binding properties of the tellurite resistance protein TerD from Klebsiella pneumoniae. The tellurium oxyanion TeO(3)(2-) has been used in the treatment of infectious diseases caused by mycobacteria. However, many pathogenic bacteria show tellurite resistance. Several tellurite resistance genes have been identified, and these genes mediate responses to diverse extracellular stimuli, but the mechanisms underlying their functions are unknown. To shed light on the function of KP-TerD, a 20.5 -kDa tellurite resistance protein from a plasmid of Klebsiella pneumoniae, we have determined its three-dimensional structure in solution using NMR spectroscopy. KP-TerD contains a β-sandwich formed by two five-stranded β-sheets and six short helices. The structure exhibits two negative clusters in loop regions on the top of the sandwich, suggesting that KP-TerD may bind metal ions. Indeed, thermal denaturation experiments monitored by circular dichroism and NMR studies reveal that KP-TerD binds Ca(2+). Inductively coupled plasma-optical emission spectroscopy shows that the binding ratio of KP-TerD to Ca(2+) is 1:2. EDTA (ethylenediaminetetraacetic acid) titrations of Ca(2+)-saturated KP-TerD monitored by one-dimensional NMR yield estimated dissociation constants of 18 and 200 nM for the two Ca(2+)-binding sites of KP-TerD. NMR structures incorporating two Ca(2+) ions define a novel bipartite Ca(2)(+)-binding motif that is predicted to be highly conserved in TerD proteins. Moreover, these Ca(2+)-binding sites are also predicted to be present in two additional tellurite resistance proteins, TerE and TerZ. These results suggest that some form of Ca(2+) signaling plays a crucial role in tellurite resistance and in other responses of bacteria to multiple external stimuli that depend on the Ter genes. | 2011 | 21112337 |
| 6151 | 14 | 0.9883 | Novel arsenic hyper-resistant bacteria from an extreme environment, Crven Dol mine, Allchar, North Macedonia. Novel hyper-resistant bacteria were isolated from the Crven Dol mine (Allchar, North Macedonia), arsenic-rich extreme environment. Bacteria were recovered from a secondary mineral mixture, an alteration of hydrothermal realgar rich in arsenates (pharmacolite, hornesite, and talmessite). The sample was recovered from the dark part of the mine at 28 m depth. Three bacterial strains and a bacterial consortium were isolated for their capacity to survive exposure to 32 g/L (209 mM) of arsenite, and 176 g/L (564 mM) of arsenate. The 16S rRNA gene analysis identified bacterial isolates as Stenotrophomonas sp. and two Microbacterium spp. This analysis also revealed that bacterial consortium comprise two Bacteriodetes exhibiting similarity to Olivibacter ginsengisoli and to uncultured bacterium, and one γ-proteobacteria with similarity to Luteimonas sp. Among all isolates Stenotrophomonas sp. exhibited the highest tolerance to As compound as well as the capacity to accumulate As inside the cells. Analysis of genes involved in As-resistance showed that recovered isolates possess the genes encoding the ArsB, Acr3(1) and Acr3(2) proteins, indicating that at least a part of their resistance could be ascribed to As-efflux systems described in isolates obtained from human-polluted environments. | 2021 | 32712355 |
| 123 | 15 | 0.9883 | Genes for all metals--a bacterial view of the periodic table. The 1996 Thom Award Lecture. Bacterial chromosomes have genes for transport proteins for inorganic nutrient cations and oxyanions, such as NH4+, K+, Mg2+, Co2+, Fe3+, Mn2+, Zn2+ and other trace cations, and PO4(3-), SO4(2-) and less abundant oxyanions. Together these account for perhaps a few hundred genes in many bacteria. Bacterial plasmids encode resistance systems for toxic metal and metalloid ions including Ag+, AsO2-, AsO4(3-), Cd2+, Co2+, CrO4(2-), Cu2+, Hg2+, Ni2+, Pb2+, TeO3(2-), Tl+ and Zn2+. Most resistance systems function by energy-dependent efflux of toxic ions. A few involve enzymatic (mostly redox) transformations. Some of the efflux resistance systems are ATPases and others are chemiosmotic ion/proton exchangers. The Cd(2+)-resistance cation pump of Gram-positive bacteria is membrane P-type ATPase, which has been labeled with 32P from [gamma-32P]ATP and drives ATP-dependent Cd2+ (and Zn2+) transport by membrane vesicles. The genes defective in the human hereditary diseases of copper metabolism, Menkes syndrome and Wilson's disease, encode P-type ATPases that are similar to bacterial cadmium ATPases. The arsenic resistance system transports arsenite [As(III)], alternatively with the ArsB polypeptide functioning as a chemiosmotic efflux transporter or with two polypeptides, ArsB and ArsA, functioning as an ATPase. The third protein of the arsenic resistance system is an enzyme that reduces intracellular arsenate [As(V)] to arsenite [As(III)], the substrate of the efflux system. In Gram-negative cells, a three polypeptide complex functions as a chemiosmotic cation/protein exchanger to efflux Cd2+, Zn2+ and Co2+. This pump consists of an inner membrane (CzcA), an outer membrane (CzcC) and a membrane-spanning (CzcB) protein that function together. | 1998 | 9523453 |
| 6213 | 16 | 0.9883 | Use of a Dictyostelium model for isolation of genetic loci associated with phagocytosis and virulence in Klebsiella pneumoniae. Phagocytosis resistance is an important virulence factor in Klebsiella pneumoniae. Dictyostelium has been used to study the interaction between phagocytes and bacteria because of its similarity to mammalian macrophages. In this study, we used a Dictyostelium model to investigate genes for resistance to phagocytosis in NTUH-K2044, a strain of K. pneumoniae causing pyogenic liver abscess that is highly resistant to phagocytosis. A total of 2,500 transposon mutants were screened by plaque assay, and 29 of them permitted phagocytosis by Dictyostelium. In the 29 mutants, six loci were identified; three were capsular synthesis genes. Of the other three, one was related to carnitine metabolism, one encoded a subunit of protease (clpX), and one encoded a lipopolysaccharide O-antigen transporter (wzm). Deletion and complementation of these genes showed that only ΔclpX and Δwzm mutants became susceptible to Dictyostelium phagocytosis, and their complementation restored the phagocytosis resistance phenotype. These two mutants were also susceptible to phagocytosis by human neutrophils and revealed attenuated virulence in a mouse model, implying that they play important roles in the pathogenesis of K. pneumoniae. Furthermore, we demonstrated that clpP, which exists in an operon with clpX, was also involved in resistance to phagocytosis. The transcriptional profile of ΔclpX was examined by microarray analysis and revealed a 3-fold lower level of expression of capsular synthesis genes. Therefore, we have identified genes involved in resistance to phagocytosis in K. pneumoniae using Dictyostelium, and this model is useful to explore genes associated with resistance to phagocytosis in heavily encapsulated bacteria. | 2011 | 21173313 |
| 185 | 17 | 0.9883 | The chromosomal arsenic resistance genes of Thiobacillus ferrooxidans have an unusual arrangement and confer increased arsenic and antimony resistance to Escherichia coli. The chromosomal arsenic resistance genes of the acidophilic, chemolithoautotrophic, biomining bacterium Thiobacillus ferrooxidans were cloned and sequenced. Homologues of four arsenic resistance genes, arsB, arsC, arsH, and a putative arsR gene, were identified. The T. ferrooxidans arsB (arsenite export) and arsC (arsenate reductase) gene products were functional when they were cloned in an Escherichia coli ars deletion mutant and conferred increased resistance to arsenite, arsenate, and antimony. Therefore, despite the fact that the ars genes originated from an obligately acidophilic bacterium, they were functional in E. coli. Although T. ferrooxidans is gram negative, its ArsC was more closely related to the ArsC molecules of gram-positive bacteria. Furthermore, a functional trxA (thioredoxin) gene was required for ArsC-mediated arsenate resistance in E. coli; this finding confirmed the gram-positive ArsC-like status of this resistance and indicated that the division of ArsC molecules based on Gram staining results is artificial. Although arsH was expressed in an E. coli-derived in vitro transcription-translation system, ArsH was not required for and did not enhance arsenic resistance in E. coli. The T. ferrooxidans ars genes were arranged in an unusual manner, and the putative arsR and arsC genes and the arsBH genes were translated in opposite directions. This divergent orientation was conserved in the four T. ferrooxidans strains investigated. | 2000 | 10788346 |
| 555 | 18 | 0.9883 | Mutations in dsbA and dsbB, but not dsbC, lead to an enhanced sensitivity of Escherichia coli to Hg2+ and Cd2+. The Dsb proteins are involved in disulfide bond formation, reduction and isomerisation in a number of Gram-negative bacteria. Mutations in dsbA or dsbB, but not dsbC, increase the proportion of proteins with free thiols in the periplasm compared to wild-type. We investigated the effects of mutations in these genes on the bacterial resistance to mercuric and cadmium salts. Mutations in genes involved primarily in disulfide formation (dsbA and dsbB) generally enhanced the sensitivity to Hg2+ and Cd2+ while a mutation of the dsbC gene (primarily an isomerase of disulfide bonds) had no effect. Mutations of the dsb genes had no effect on the expression of the mercury-resistance determinants of the transposon Tn501. | 1999 | 10234837 |
| 634 | 19 | 0.9882 | Role of the Escherichia coli SbmA in the antimicrobial activity of proline-rich peptides. In contrast to many antimicrobial peptides, members of the proline-rich group of antimicrobial peptides inactivate Gram-negative bacteria by a non-lytic mechanism. Several lines of evidence indicate that they are internalized into bacteria and their activity mediated by interaction with unknown cellular components. With the aim of identifying such interactors, we selected mutagenized Escherichia coli clones resistant to the proline-rich Bac7(1-35) peptide and analysed genes responsible for conferring resistance, whose products may thus be involved in the peptide's mode of action. We isolated a number of genomic regions bearing such genes, and one in particular coding for SbmA, an inner membrane protein predicted to be part of an ABC transporter. An E. coli strain carrying a point mutation in sbmA, as well as other sbmA-null mutants, in fact showed resistance to several proline-rich peptides but not to representative membranolytic peptides. Use of fluorescently labelled Bac7(1-35) confirmed that resistance correlated with a decreased ability to internalize the peptide, suggesting that a bacterial protein, SbmA, is necessary for the transport of, and for susceptibility to, proline-rich antimicrobial peptides of eukaryotic origin. | 2007 | 17725560 |