In silico identification of potential chaperone genes that belong to type III and type IV secretion systems in Xanthomonas axonopodis pv citri

Khater, Letícia; Santos, Túlio M.; Alegria, Marcos C.; Docena, Cássia; Silva, Ana C. R. da; Ramos, Carlos H.I.

doi:10.1590/s1415-47572005000200024

Cited by 4 publications

(1 citation statement)

References 53 publications

(53 reference statements)

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“…Some literatures stipulate that secretion of most effectors was reduced but not abolished in the absence of their chaperones [ 46 – 51 ]. Recent reviews on flagellar chaperones, however, have stated that flagellar chaperones might be required mainly to prevent premature interactions between subunits of the flagellum by masking their interaction domains [ 52 ]. The result of the present study shows that the absence of the potential chaperone genes halts the secretion of the effector proteins in Pcc .…”

Section: Discussionmentioning

confidence: 99%

Injectisome T3SS subunits as potential chaperones in the extracellular export of Pectobacterium carotovorum subsp. carotovorum bacteriocins Carocin S1 and Carocin S3 secreted via flagellar T3SS

Derilo

Chen

et al. 2021

BMC Microbiol

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Pectobacterium carotovorum subsp. carotovorum (Pcc) causes soft-rot disease in a wide variety of plants resulting in economic losses worldwide. It produces various types of bacteriocin to compete against related plant pathogens. Studies on how bacteriocins are extracellularly secreted are conducted to understand the mechanism of interbacterial competition. In this study, the secretion of the low-molecular-weight bacteriocins (LMWB) Carocin S1 and Carocin S3 produced by a multiple-bacteriocin producing strain of Pcc, 89-H-4, was investigated. Tn5 insertional mutagenesis was used to generate a mutant, TH22–6, incapable of LMWBs secretion. Sequence and homology analyses of the gene disrupted by transposon Tn5 insertion revealed that the gene sctT, an essential component of the injectisome type III secretion machinery (T3aSS), is required for the secretion of the bacteriocins. This result raised a question regarding the nature of the secretion mechanism of Pcc bacteriocins which was previously discovered to be secreted via T3bSS, a system that utilizes the bacterial flagellum for extracellular secretions. Our previous report has shown that bacteriocin Carocin S1 cannot be secreted by mutants that are defective of T3bSS-related genes such as flhA, flhC, flhD and fliC. We knocked out several genes making up the significant structural components of both T3aSS and T3bSS. The findings led us to hypothesize the potential roles of the T3aSS-related proteins, SctT, SctU and SctV, as flagellar T3SS chaperones in the secretion of Pcc bacteriocins. This current discovery and the findings of our previous study helped us to conceptualize a unique Type III secretion system for bacteriocin extracellular export which is a hybrid of the injectisome and flagellar secretion systems.

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Section: Discussionmentioning

confidence: 99%

Injectisome T3SS subunits as potential chaperones in the extracellular export of Pectobacterium carotovorum subsp. carotovorum bacteriocins Carocin S1 and Carocin S3 secreted via flagellar T3SS

Derilo

Chen

et al. 2021

BMC Microbiol

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Identification of the flagellar chaperone FlgN in the phytopathogen Xanthomonas axonopodis pathovar citri by its interaction with hook-associated FlgK

et al. 2007

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Genome annotation of the plant pathogen Xanthomonas axonopodis pv. citri (Xac), identified flagellar genes in a 15.7 kb gene cluster. However, FlgN, a secretion chaperone for hook-associated proteins FlgK and FlgL, was not identified. We performed extensive screening of the X. axonopodis pv. citri genome with the yeast two-hybrid system to identify a protein with the characteristics of the flagellar chaperone FlgN. We found a candidate (XAC1990) encoded by an operon for components of the flagellum apparatus that interacted with FlgK. In order to further support this finding, Xac FlgK and XAC1990 were cloned, expressed, and purified. The recombinant proteins were characterized by spectroscopic methods and their interaction in vitro confirmed by pull-down assays. We, therefore, conclude that XAC1990 and its homologs in other Xanthomonas species are, in fact, FlgN proteins. These observations extend the sequence diversity covered by this family of proteins.

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Structural Insights on Two Hypothetical Secretion Chaperones from Xanthomonas axonopodis pv. citri

et al. 2011

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Several Gram-negative bacterial pathogens have developed type III secretion systems (T3SSs) to deliver virulence proteins directly into eukaryotic cells in a process essential for many diseases. The type III secretion processes require customized chaperones with high specificity for binding partners, thus providing the secretion to occur. Due to the very low sequence similarities among secretion chaperones, annotation and discrimination of a great majority of them is extremely difficult and a task with low scores even if genes are encountered that codify for small (<20 kDa) proteins with low pI and a tendency to dimerise. Concerning about this, herein, we present structural features on two hypothetical T3SSs chaperones belonging to plant pathogen Xanthomonas axonopodis pv. citri and suggest how low resolution models based on Small Angle X-ray Scattering patterns can provide new structural insights that could be very helpful in their analysis and posterior classification.

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In silico identification of potential chaperone genes that belong to type III and type IV secretion systems in Xanthomonas axonopodis pv citri

Cited by 4 publications

References 53 publications

Injectisome T3SS subunits as potential chaperones in the extracellular export of Pectobacterium carotovorum subsp. carotovorum bacteriocins Carocin S1 and Carocin S3 secreted via flagellar T3SS

Injectisome T3SS subunits as potential chaperones in the extracellular export of Pectobacterium carotovorum subsp. carotovorum bacteriocins Carocin S1 and Carocin S3 secreted via flagellar T3SS

Identification of the flagellar chaperone FlgN in the phytopathogen Xanthomonas axonopodis pathovar citri by its interaction with hook-associated FlgK

Structural Insights on Two Hypothetical Secretion Chaperones from Xanthomonas axonopodis pv. citri

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