Metabolic Remodeling during Nitrogen Fixation in Zymomonas
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ABSTRACT:
INSTRUMENT(S): Orbitrap Eclipse
ORGANISM(S): Zymomonas Mobilis Subsp. Mobilis Zm4 = Atcc 31821
SUBMITTER: 
Katherine Overmyer
LAB HEAD: Joshua J Coon
PROVIDER: PXD028526 | Pride | 2021-10-07
REPOSITORIES: Pride
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Project description:Limited functional annotation of the Z. mobilis genome is a current barrier to both basic studies of Z. mobilis and its development as a synthetic-biology chassis. To gain insight, we collected sample-matched multiomics data including RNA-seq, transcription start site sequencing (TSS-seq), termination sequencing (term-seq), ribosome profiling, and label-free shotgun proteomic mass spectrometry across different growth conditions to improve annotation and assign functional sites in the Z. mobilis genome. Proteomics and ribosome profiling informed revisions of protein-coding genes, which included 44 start codon changes and 42 added proteins.
2020-07-10 | PXD016962 | Pride
Project description:Previously we found that modified Zymomonas mobilis is able to convert glucose to ethanol when fermenting highly concentrated hydrolysates such as 9% glucan-loading AFEX-pretreated corn stover hydrolysate (ACSH), but that xylose conversion after glucose depletion is greatly impaired. We hypothesized that impaired xylose conversion is caused by lignocellulose-derived inhibitors (LDIs) present in highly concentrated hydrolysates. To investigate the effects of LDIs on xylose utilization in Z. mobilis, we generated synthetic hydrolysates (SynHs) that contains nutrients and LDI at concentrations found in authentic 9% ACSH. Comparative fermentations of Z. mobilis 2032 using SynH with or without LDI were performed, and samples were collected for endproduct, transcriptomic, metabolomic, and proteomic analyses. Our data suggest that the overall flux of xylose metabolism is reduced in the presence of LDIs. However, the expression of most genes involved in glucose and xylose assimilation was not affected by LDIs nor did we observe blocks in glucose and xylose metabolic pathways. Several LDI-specific effects were observed including intracellular accumulation of mannose-1P and mannose-6P, down regulation of a Type I secretion system (ZMO0252-0255), and upregulation of sulfur metabolism genes and the RND family efflux pump system (ZMO0282_0283_0285). This efflux pump system is involved in detoxification. Together, our findings identify cellular responses to LDIs and possible causes of impaired xylose conversion that will enable future strain engineering of Z. mobilis.
2019-10-28 | PXD015007 | Pride
Project description:We engineered Z. mobilis ZM4 to express a recombinant glycosyl hydrolase (GH) from Caulobacter crescentus and subjected it to an adaptation in cellobiose medium. Growth on cellobiose was achieved after a prolonged lag phase in cellobiose medium that induced changes in gene expression and cell composition, including increased expression and secretion of GH. These changes were found to be reversible, i.e. not a genetic adaptation, but could be preserved upon transfer to fresh cellobiose medium. After adaptation to cellobiose, our GH expressing strain was able to convert about 50% of cellobiose to glucose within 24 h and use it for growth and ethanol production. Alternatively, adaptation by growth in sucrose medium also enabled immediate growth of Z. mobilis GH3 on cellobiose. Proteomics analysis of cellobiose- and sucrose-adapted strains revealed upregulation of secretion-, transport-, and outer membrane-related proteins, which may aid secretion of GH into the medium. Changes in the cell envelope may additionally enable entry of cellobiose into the cell periplasm or surface display of GHs.
2020-07-29 | PXD015770 | Pride
Project description:Protein phosphorylation is an important post translational modification that plays a major role in cellular regulatory processes in both eukaryotes and prokaryotes. In recent years, aided by advancements in mass spectrometry techniques, there has been a growing interest in studying protein phosphorylation in prokaryotic model organisms. There are, however, only a limited number of phosphoproteomics reports on non-model organisms. Here, using mass spectrometry, we performed a genome wide investigation of protein phosphorylation in the non-model organism and biofuel producer Zymomonas mobilis under anaerobic, aerobic, and N2-fixing conditions. Our phosphoproteome analysis revealed 125 unique phosphorylated proteins and 172 unique phosphopeptides across these three growth conditions. The phosphoproteins identified belonged to major pathways, including glycolysis, TCA cycle, protein biosynthesis, electron transport, and nitrogen fixation. Quantitative analysis revealed significant and widespread changes in protein phosphorylation across anaerobic, aerobic, and N2-fixing growth conditions. For example, two different serine residues of KDPG aldolase, an Entner-Doudoroff pathway enzyme, were differentially phosphorylated under aerobic and N2-fixing conditions. On the other hand, the final enzyme in the ethanol fermentation pathway, alcohol dehydrogenase, showed phosphorylation on its Ser99 only under N2-fixing condition while its Ser126 was only phosphorylated under anaerobic condition. Moreover, nitrogenases and nitrogen regulatory proteins were differentially phosphorylated at multiple sites under aerobic and N2-fixing conditions. Altogether, this study provides new knowledge regarding potential phosphorylation regulatory sites of specific proteins in pathways relevant to ethanol production and overall physiology and establishes new ground for future engineering of Z. mobilis for advanced biofuel production.
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2019-01-18 | PXD011545 | Pride
Project description:Background: Lysine crotonylation (Kcr), as a novel evolutionarily conserved type of PTM, is ubiquitous and essential in cell biology. However, its functions in tea plant, an important beverage crop, are largely unknown. Our study firstly attempted to describe Kcr proteins in tea leaves under NH4+ deficiency/resupply, and provided significant insights into exploring the physiological role of Kcr in plants for N utilization. Results: We performed the global analysis of crotonylome in tea plants under NH4+ deficiency/resupply using high-resolution LC-MS/MS coupled with highly sensitive immune-antibody. A total of 2288 kcr sites on 971 proteins were identified, of which contained in 15 types of Kcr motifs. Most of Kcr proteins were located in chloroplast and cytoplasm. 120 and 151 Kcr proteins were significantly changed at 3 hours and 3days of NH4+ resupply, respectively. Bioinformatics analysis showed that differentially expressed Kcr proteins participated in diverse biological processes such as photosynthesis, carbon fixation and amino acid metabolism, suggesting Kcr plays important roles in these processes. Interestingly, a large number of enzymes were crotonylated, and the activity and Kcr level of these enzymes changed significantly after NH4+ resupply, indicating a potential function of Kcr in the regulation of enzyme activities. Moreover, the protein-protein interaction analysis revealed that the diverse interactions of identified Kcr proteins mainly involved in photosynthesis, carbon fixation, amino acid metabolism and ribosome. Conclusions: The results suggested that lysine crotonylated proteins might play regulating roles in metabolic process in tea leaves under NH4+ deficiency/resupply. The critical regulatory roles mainly involved in diverse aspects of primary metabolic processes, especially in photosynthesis, carbon fixation and amino acid metabolism. The provided data may serve as important resources for exploring the physiological, biochemical, and genetic role of lysine crotonylation in tea plants.
2019-05-09 | PXD011610 | Pride
Project description:Traumatic brain injury (TBI) pathologies are caused by primary and secondary injuries. Primary injuries result from physical damage to the brain, and secondary injuries arise from cellular responses to primary injuries. A characteristic cellular response is sustained activation of inflammatory pathways commonly mediated by NF-B transcription factors. Using a Drosophila melanogaster TBI model, we previously found that the main proximal transcriptional response to primary injuries is triggered by activation of Toll and Imd innate immune response pathways that engage NF-B factors Dif and Relish (Rel), respectively. Here, we monitor the abundance of Rel protein by mass spectrometry (MS) and observe that Rel increases in fly heads at 4-8 h after TBI. To investigate the necessity of Rel for secondary injuries, we generated a null allele, Reldel, by CRISPR/Cas9 editing. Heterozygous but not homozygous Reldel mutation reduced mortality at 24 h after TBI and increased the lifespan of injured flies. Additionally, the effect of heterozygous Reldel mutation on mortality was modulated by genetic background and diet. To identify genes that facilitate effects of heterozygous Reldel mutation on TBI outcomes, we compared genome-wide mRNA expression profiles of uninjured and injured +/+, +/Reldel, and Reldel/Reldel flies at 4 h following TBI. Only a few genes changed expression more than two-fold in +/Reldel flies relative to +/+ and Reldel/Reldel flies, and they were not canonical innate immune response genes. Therefore, Rel is necessary for TBI-induced secondary injuries but in complex ways involving Rel gene dose, genetic background, diet, and possibly small changes in expression of innate immune response genes.
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Project description:We herein conducted high throughput analyses of proteome and protein acetylation in Z. mobilis under N2-fixing conditions, and established its first acetylome.
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