ESX-main.zip

Since the release of vSphere 7.0, VMware has distributed an add-on .zip file that contains the delta between the OEM custom image and the base image that VMware provides. So, you can download the original VMware ESXi image and custom ISO images, as well as those OEM add-ons.

ESX-main.zip

We'll create an offline depot and then import the ZIP file we have downloaded from VMware. We're using the latest VMware-ESXi-7.0U2a-17867351-depot.zip file (offline bundle), available in the MyVMware account.

ABSTRACT The type VII secretion systems are conserved across mycobacterial species and in many Gram-positive bacteria. While the well-characterized Esx-1 pathway is required for the virulence of pathogenic mycobacteria and conjugation in the model organism Mycobacterium smegmatis, Esx-3 contributes to mycobactin-mediated iron acquisition in these bacteria. Here we show that several Esx-3 components are individually required for function under low-iron conditions but that at least one, the membrane-bound protease MycP3 of M. smegmatis, is partially expendable. All of the esx-3 mutants tested, including the ΔmycP3ms mutant, failed to export the native Esx-3 substrates EsxHms and EsxGms to quantifiable levels, as determined by targeted mass spectrometry. Although we were able to restore low-iron growth to the esx-3 mutants by genetic complementation, we found a wide range of complementation levels for protein export. Indeed, minute quantities of extracellular EsxHms and EsxGms were sufficient for iron acquisition under our experimental conditions. The apparent separation of Esx-3 function in iron acquisition from robust EsxGms and EsxHms secretion in the ΔmycP3ms mutant and in some of the complemented esx-3 mutants compels reexamination of the structure-function relationships for type VII secretion systems. IMPORTANCE Mycobacteria have several paralogous type VII secretion systems, Esx-1 through Esx-5. Whereas Esx-1 is required for pathogenic mycobacteria to grow within an infected host, Esx-3 is essential for growth in vitro. We and others have shown that Esx-3 is required for siderophore-mediated iron acquisition. In this work, we identify individual Esx-3 components that contribute to this process. As in the Esx-1 system, most mutations that abolish Esx-3 protein export also disrupt its function. Unexpectedly, however, ultrasensitive quantitation of Esx-3 secretion by multiple-reaction-monitoring mass spectrometry (MRM-MS) revealed that very low levels of export were sufficient for iron acquisition under similar conditions. Although protein export clearly contributes to type VII function, the relationship is not absolute.

The Type VII secretion system (T7SS or MPSS); the ESAT-6-like protein secretion system, ESX-5 (Abdallah et al., 2006; Sayes et al., 2012; Houben et al. 2012). Mediates the secretion of the EsxN, PPE [pro-pro-glu motif] and PE_PGRS proteins (Deng and Xie 2012). The EccB5, EccC5, EccD5 and EccE5 proteins form a membrane complex of about 1.5 MDa while EccA5 may be the channel-forming subunit that exports the substrate proteins (Bunduc et al. 2021). Thus, ESX-5 exports protein substrate (Houben et al. 2012). PE25/PPE41form a heterodimer that is targeted to the T7SS, ESX5, by a C-terminal signal in PE25 which is necessary but not sufficient for targeting to ESX5 (Daleke et al. 2012). An esx-5 mutant is strongly impaired in the uptake and utilization of hydrophobic carbon sources. Possibly the ESX-5 system is responsible for the transport of cell envelope proteins that are required for nutrient uptake (Ates et al. 2015). Mycobacterium tuberculosis releases membrane vesicles (MV) that modulate host immune responses and aid in iron acquisition, and the ESX-5 system seems to play a role, together with the SenX3-RegX3 complex which regulates the process (White et al. 2018). The 3-D structure of ESX-5 has been determined (Bunduc et al. 2021) (see ESX5 family description, paragraph 11 for details). The structure of the mycobacterial ESX-5 type VII secretion system pore complex has been determined (Beckham et al. 2021). The high-resolution structure of the 2.1-megadalton ESX-5 core complex captured a dynamic, secretion-competent conformation of the pore within a well-defined transmembrane section, sandwiched between two flexible protein layers at the cytosolic entrance and the periplasmic exit. Beckham et al. 2021 proposed that this flexibility endows the ESX-5 machinery with large conformational plasticity required to accommodate targeted protein secretion. A highly dynamic state of the pore may represent a fundamental principle of bacterial secretion machineries. 041b061a72