Analysis of proteins in<i>Chlamydia trachomatis</i>L2 outer membrane complex, COMC

Birkelund, Svend; Morgan-Fisher, Marie; Timmerman, Evy; Gevaert, Kris; Shaw, Andrew; Christiansen, Gunna

doi:10.1111/j.1574-695x.2009.00522.x

Cited by 25 publications

(24 citation statements)

References 38 publications

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“…PmpB, PmpC, PmpE, PmpF, PmpG, and PmpH all were significantly enriched in COMC, which is in agreement with previous reports (7,51,63,64,69). Peptides corresponding to these proteins were enriched from approximately 4-fold (PmpC) to 17-fold (PmpG) in the COMC compared to that in the soluble fraction (Table 1).…”

Section: Resultssupporting

confidence: 81%

“…MOMP was almost undetectable in the soluble fraction, whereas it was clearly enriched in the COMC. COMC contained additional less intense but clear groups of protein bands in the ranges of approximately 30, 45, 60, and 70 kDa and a large number of minor bands in the range of 90 to 150 kDa, which is consistent with previous reports (7,51,64). We blotted the fractions with monoclonal antibodies targeting MOMP and the abundant soluble protein HSP60 (4) to evaluate the purity of COMC.…”

Section: Resultssupporting

confidence: 69%

“…We chose to use comparative proteomics based on reports that COMC can be contaminated with soluble proteins during purification (7,29,56). Our COMC purification was preoptimized by standardizing times and intensities of sonication and DNase I treatment steps while monitoring COMC, soluble, and whole EB fractions in parallel with Western blotting and TEM.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, not all COMC proteins are exposed on the EB surface, nor are all EB OM proteins components of the COMC. Beyond these well-described and abundant COMC components, other studies have indicated that additional proteins localize to the EB surface and/or COMC of Chlamydia trachomatis (7,28,36,51,57,64,67,70). However, confirming that specific proteins localize to the COMC or OM of EB can be challenging due to factors such as the contamination of EB preparations with RB proteins and technical limitations of proteomic and surface-labeling protein identification methods (29,56).…”

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confidence: 99%

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Identification ofChlamydia trachomatisOuter Membrane Complex Proteins by Differential Proteomics

Liu¹,

Afrane

Clemmer³

et al. 2010

J Bacteriol

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The extracellular chlamydial infectious particle, or elementary body (EB), is enveloped by an intra-and intermolecular cysteine cross-linked protein shell called the chlamydial outer membrane complex (COMC). A few abundant proteins, including the major outer membrane protein and cysteine-rich proteins (OmcA and OmcB), constitute the overwhelming majority of COMC proteins. The identification of less-abundant COMC proteins has been complicated by limitations of proteomic methodologies and the contamination of COMC fractions with abundant EB proteins. Here, we used parallel liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) analyses of Chlamydia trachomatis serovar L2 434/Bu EB, COMC, and Sarkosylsoluble EB fractions to identify proteins enriched or depleted from COMC. All well-described COMC proteins were specifically enriched in the COMC fraction. In contrast, multiple COMC-associated proteins found in previous studies were strongly enriched in the Sarkosyl-soluble fraction, suggesting that these proteins are not COMC components or are not stably associated with COMC. Importantly, we also identified novel proteins enriched in COMC. The list of COMC proteins identified in this study has provided reliable information for further understanding chlamydial protein secretion systems and modeling COMC and EB structures.Bacteria in the phylum Chlamydiae are characterized by their complex intracellular developmental cycles. Chlamydiae must assume at least two functionally distinct morphotypes, the intracellular, replicative reticulate body (RB) and the extracellular, infectious elementary body (EB), to replicate and be transmitted to new hosts (50). The divergence of distinct RB and EB forms may have been driven by the different pressures these pathogens face inside host cells during replication and outside host cells during transmission. For example, the outer membrane of EB contains a poorly immunogenic truncated lipopolysaccharide (LPS) (14, 30) and immunodominant epitopes of the major outer membrane protein (MOMP) vary substantially among closely related chlamydial strains (13). EB also lack detectable peptidoglycan (2, 20, 60), although functional murein biosynthetic enzymes (2,5,16,21,32,43,45,46) are expressed in RB during productive and persistent infection (44). To compensate for the loss of murein, EB are enveloped by a protein P-layer, which lends osmotic stability to the infectious particle (29).Attempts to identify components of the P-layer and outer membrane proteins of Chlamydia were advanced by the observation that these layers can be separated from many soluble EB proteins using the detergent N-lauroyl sarcosine (Sarkosyl). Caldwell et al. dubbed the Sarkosyl-insoluble fraction the chlamydial outer membrane complex (COMC) and noted that purified COMC maintained the shape of intact EB and contained a complete outer membrane, and they reported that a single outer membrane protein, MOMP, accounted for more than 60% of total COMC protein content (15). Other studies revealed that the COMC is ...

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Section: Resultssupporting

confidence: 81%

Section: Resultssupporting

confidence: 69%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Identification ofChlamydia trachomatisOuter Membrane Complex Proteins by Differential Proteomics

Liu¹,

Afrane

Clemmer³

et al. 2010

J Bacteriol

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“…jjStrain 2032/99 does not have a plasmid. # (Aistleitner, 2015;Birkelund et al, 2009;Frandi et al, 2014;Jacquier et al, 2014;Kebbi-Beghdadi et al, 2015;Liechti et al, 2014;Pilhofer et al, 2014Pilhofer et al, , 2013. **Putative Pom encoded in the genome, but not isolated at the membrane.…”

Section: Cell Wall and Surface Proteinsmentioning

confidence: 99%

Simkania negevensis, an insight into the biology and clinical importance of a novel member of the Chlamydiales order

Vouga

Baud

Greub

2016

Critical Reviews in Microbiology

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Simkania negevensis is a Chlamydia-related bacterium discovered in 1993 and represents the founding member of the Simkaniaceae family within the Chlamydiales order. As other Chlamydiales, it is an obligate intracellular bacterium characterized by a biphasic developmental cycle. Its similarities with the pathogenic Chlamydia trachomatis and Chlamydia pneumoniae make it an interesting bacterium. So far, little is known about its biology, but S. negevensis harbors various microbiological characteristics of interest, including a strong association of the Simkania-containing vacuole with the ER and the presence of an intron in the 23S rRNA encoding gene. Evidence of human exposition has been reported worldwide. However, there is a lack of robust clinical studies evaluating its implication in human diseases; current data suggest an association with pneumonia and bronchiolitis making S. negevensis a potential emerging pathogen. Owing to its fastidious growth requirements, the clinical relevance of S. negevensis is probably underestimated. In this review, we summarize the current knowledge on S. negevensis and explore future research challenges. ARTICLE HISTORY

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Avian Chlamydiosis

Vanrompay¹

2019

Diseases of Poultry

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Analysis of proteins inChlamydia trachomatisL2 outer membrane complex, COMC

Cited by 25 publications

References 38 publications

Identification ofChlamydia trachomatisOuter Membrane Complex Proteins by Differential Proteomics

Identification ofChlamydia trachomatisOuter Membrane Complex Proteins by Differential Proteomics

Simkania negevensis, an insight into the biology and clinical importance of a novel member of the Chlamydiales order

Avian Chlamydiosis

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