scholarly journals Amino Acid Features of PIB-ATPase Heavy Metal Transporters Enabling small Numbers of Organisms to Cope with Heavy Metal Pollution

2011 ◽  
Vol 5 ◽  
pp. BBI.S6206 ◽  
Author(s):  
E. Ashrafi ◽  
A. Alemzadeh ◽  
M. Ebrahimi ◽  
E. Ebrahimie ◽  
N. Dadkhodaei ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ion ◽  
Ion Homeostasis ◽  
Structural Features ◽  
Site Directed Mutagenesis ◽  
Structural Protein ◽  
Tertiary Structures ◽  
Metal Transporters ◽  
Metal Ion Homeostasis ◽  
Wide Range

Phytoremediation refers to the use of plants for extraction and detoxification of pollutants, providing a new and powerful weapon against a polluted environment. In some plants, such as Thlaspi spp, heavy metal ATPases are involved in overall metal ion homeostasis and hyperaccumulation. P1B-ATPases pump a wide range of cations, especially heavy metals, across membranes against their electrochemical gradients. Determination of the protein characteristics of P1B-ATPases in hyperaccumulator plants provides a new opportuntity for engineering of phytoremediating plants. In this study, using diverse weighting and modeling approaches, 2644 protein characteristics of primary, secondary, and tertiary structures of P1B-ATPases in hyperaccumulator and nonhyperaccumulator plants were extracted and compared to identify differences between proteins in hyperaccumulator and nonhyperaccumulator pumps. Although the protein characteristics were variable in their weighting, tree and rule induction models; glycine count, frequency of glutamine-valine, and valine-phenylalanine count were the most important attributes highlighted by 10, five, and four models, respectively. In addition, a precise model was built to discriminate P1B-ATPases in different organisms based on their structural protein features. Moreover, reliable models for prediction of the hyperaccumulating activity of unknown P1B-ATPase pumps were developed. Uncovering important structural features of hyperaccumulator pumps in this study has provided the knowledge required for future modification and engineering of these pumps by techniques such as site-directed mutagenesis.

scholarly journals Proteome Profile Changes During Poly-hydroxybutyrate Intracellular Mobilization in Gram Positive Bacillus cereus tsu1

2019 ◽  
Author(s):  
HUI LI ◽  
Joshua O’Hair ◽  
Santosh Thapa ◽  
Sarabjit Bhatti ◽  
Suping Zhou ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Metal Ion ◽  
Ion Homeostasis ◽  
Carbon Sources ◽  
Nucleotide Metabolism ◽  
Nitrate Respiration ◽  
Metal Ion Homeostasis ◽  
Wide Range ◽  
Profile Changes ◽  
Proteome Profile

Abstract Background Bacillus cereus is a bacterium species can grow efficiently on a wide range of carbon sources and accumulate biopolymer poly-hydroxybutyrate (PHB) up to 80% cell dry weight. PHB is an aliphatic polymer produced and stored intracellularly as a reservoir of carbon and energy, its mobilization is a key biological process for the spore forming Bacillus spp . Our lab previously isolated and identified a bacterial strain Bacillus cereus tsu1. The bacterium was cultured on rapeseed cake substrate (RCS) and the maxima of PHB accumulation reached within 12 h, and depleted after 48 h; fore-spore and spore structure were observed after 24 h culture.Results Quantitative proteomic analysis of ‘ tsu1’ identified 3,215 proteins in total, out of which 2,952 got quantified. 244 were identified as significantly changed proteins (SCPs) in the 12-24-hour pair of samples, and 325 in the12-48-hour pair of samples. Gene Ontology classification revealed that enriched biological processes only found in the 12-24h pair SCPs include purine nucleotide metabolism, protein folding, metal ion homeostasis, response to stress, carboxylic acid catabolism, cellular amino acid catabolism; and those only found in the 12-48h pair SCPs were carbohydrate metabolism, protein metabolism, oxidative phosphorylation, formation of translation ternary structure. Based on statistical analysis, key enzymes poly(R)-hydroxyalkanoic acid synthase (PhaC, KGT44864) is significantly higher in 12h-culture; SigF, SpoEII related with sporulation were significantly higher in the 24h-samples; enzymes for nitrate respiration and fermentation were significantly induced in 48h-culture.Conclusions Proteome profile changes during PHB intracellular mobilization in B. cereus tsu1 were characterized in this study. The key enzyme PhaC for PHB synthesis is significantly higher in 12h-culture which supports the highest PHB accumulation at this time point; protein abundance of SpoIIE and σF were significantly increased to induce sporulation in 24h-culture; enzymes for nitrate respiration and fermentation were significantly induced in 48h-culture which implied the depletion of oxygen at this stage and carbon flow towards fermentative growth. The results from this study provide insights into proteome profile changes during PHB accumulation and reuse, which can be applied to achieve a higher PHB yield and to improve bacterial growth performance and stress resistance.

scholarly journals The molecular basis of Acinetobacter baumannii cadmium toxicity and resistance

2020 ◽  
Author(s):  
Saleh F. Alquethamy ◽  
Felise G. Adams ◽  
Ram Maharjan ◽  
Natasha N. Delgado ◽  
Maoge Zang ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Acinetobacter Baumannii ◽  
Metal Ion ◽  
Cadmium Toxicity ◽  
Ion Homeostasis ◽  
Cadmium Stress ◽  
Primary Role ◽  
Metal Ion Homeostasis ◽  
Primary Means ◽  
The Impact

ABSTRACTAcinetobacter species are ubiquitous Gram-negative bacteria that can be found in water, soil and as commensals of the human skin. The successful inhabitation of Acinetobacter species in diverse environments is primarily attributable to the expression of an arsenal of stress resistance determinants, which includes an extensive repertoire of metal ion efflux systems. Although metal ion homeostasis in the hospital pathogen Acinetobacter baumannii is known to contribute to pathogenesis, insights into its metal ion transporters for environmental persistence are lacking. Here, we studied the impact of cadmium stress on A. baumannii. Our functional genomics and independent mutant analyses revealed a primary role for CzcE, a member of the cation diffusion facilitator (CDF) superfamily, in resisting cadmium stress. Further, we show that the CzcCBA heavy metal efflux system also contributes to cadmium efflux. Analysis of the A. baumannii metallome under cadmium stress showed zinc depletion and copper enrichment, which are likely to influence cellular fitness. Overall, this work expands our understanding of the role of membrane transporters in A. baumannii metal ion homeostasis.IMPORTANCECadmium toxicity is a widespread problem, yet the interaction of this heavy metal with biological systems is poorly understood. Some microbes have evolved traits to proactively counteract cadmium toxicity, which includes Acinetobacter baumannii. Here we show that A. baumannii utilises a dedicated cadmium efflux protein in concert with a system that is primarily attuned to zinc efflux, to efficiently overcome cadmium stress. The molecular characterization of A. baumannii under cadmium stress revealed how active cadmium efflux plays a key role in preventing the dysregulation of bacterial metal ion homeostasis, which appeared to be the primary means by which cadmium exerts toxicity upon the bacterium.

scholarly journals Recent Developments in Metal-Based Drugs and Chelating Agents for Neurodegenerative Diseases Treatments

2019 ◽  
Vol 20 (8) ◽  
pp. 1829 ◽  
Author(s):  
Sales ◽  
Prandi ◽  
Castro ◽  
Leal ◽  
Cunha ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Metal Ion ◽  
Chelating Agents ◽  
Ion Homeostasis ◽  
Disruptive Disorders ◽  
Metal Ion Homeostasis ◽  
Wide Range ◽  
Recent Developments ◽  
Specific Proteins ◽  
The Brain

The brain has a unique biological complexity and is responsible for important functions in the human body, such as the command of cognitive and motor functions. Disruptive disorders that affect this organ, e.g. neurodegenerative diseases (NDDs), can lead to permanent damage, impairing the patients’ quality of life and even causing death. In spite of their clinical diversity, these NDDs share common characteristics, such as the accumulation of specific proteins in the cells, the compromise of the metal ion homeostasis in the brain, among others. Despite considerable advances in understanding the mechanisms of these diseases and advances in the development of treatments, these disorders remain uncured. Considering the diversity of mechanisms that act in NDDs, a wide range of compounds have been developed to act by different means. Thus, promising compounds with contrasting properties, such as chelating agents and metal-based drugs have been proposed to act on different molecular targets as well as to contribute to the same goal, which is the treatment of NDDs. This review seeks to discuss the different roles and recent developments of metal-based drugs, such as metal complexes and metal chelating agents as a proposal for the treatment of NDDs.

scholarly journals The molecular basis of Acinetobacter baumannii cadmium toxicity and resistance

2021 ◽  
Author(s):  
Saleh F. Alquethamy ◽  
Felise G. Adams ◽  
Ram Maharjan ◽  
Natasha N. Delgado ◽  
Maoge Zang ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Acinetobacter Baumannii ◽  
Metal Ion ◽  
Cadmium Toxicity ◽  
Ion Homeostasis ◽  
Cadmium Stress ◽  
Primary Role ◽  
Metal Ion Homeostasis ◽  
Primary Means ◽  
The Impact

Acinetobacter species are ubiquitous Gram-negative bacteria that can be found in water, soil, and as commensals of the human skin. The successful inhabitation of Acinetobacter species in diverse environments is primarily attributable to the expression of an arsenal of stress resistance determinants, which includes an extensive repertoire of metal ion efflux systems. Metal ion homeostasis in the hospital pathogen Acinetobacter baumannii contributes to pathogenesis, however, insights into its metal ion transporters for environmental persistence are lacking. Here, we studied the impact of cadmium stress on A. baumannii . Our functional genomics and independent mutant analyses revealed a primary role for CzcE, a member of the cation diffusion facilitator (CDF) superfamily, in resisting cadmium stress. We also show that the CzcCBA heavy metal efflux system contributes to cadmium efflux. Collectively, these systems provide A. baumannii with a comprehensive cadmium translocation pathway from the cytoplasm to the periplasm and subsequently the extracellular space. Furthermore, analysis of the A. baumannii metallome under cadmium stress showed zinc depletion, as well as copper enrichment, which are likely to influence cellular fitness. Overall, this work provides new knowledge on the role of a broad arsenal of membrane transporters in A. baumannii metal ion homeostasis. IMPORTANCE Cadmium toxicity is a widespread problem, yet the interaction of this heavy metal with biological systems is poorly understood. Some microbes have evolved traits to proactively counteract cadmium toxicity, including Acinetobacter baumannii , which is notorious for persisting in harsh environments. Here we show that A. baumannii utilises a dedicated cadmium efflux protein in concert with a system that is primarily attuned to zinc efflux to efficiently overcome cadmium stress. The molecular characterization of A. baumannii under cadmium stress revealed how active cadmium efflux plays a key role in preventing the dysregulation of bacterial metal ion homeostasis, which appeared to be a primary means by which cadmium exerts toxicity upon the bacterium.

scholarly journals Zinc limitation in Klebsiella pneumoniae profiled by quantitative proteomics influences transcriptional regulation and cation transporter-associated capsule production

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
A. Sukumaran ◽  
S. Pladwig ◽  
J. Geddes-McAlister
Keyword(s):  
Klebsiella Pneumoniae ◽  
Metal Ion ◽  
Ion Homeostasis ◽  
Cellular Protein ◽  
Pcr Analysis ◽  
Phenotypic Analysis ◽  
Metal Ion Homeostasis ◽  
Capsule Production ◽  
The Impact

Abstract Background Microbial organisms encounter a variety of environmental conditions, including changes to metal ion availability. Metal ions play an important role in many biological processes for growth and survival. As such, microbes alter their cellular protein levels and secretion patterns in adaptation to a changing environment. This study focuses on Klebsiella pneumoniae, an opportunistic bacterium responsible for nosocomial infections. By using K. pneumoniae, we aim to determine how a nutrient-limited environment (e.g., zinc depletion) modulates the cellular proteome and secretome of the bacterium. By testing virulence in vitro, we provide novel insight into bacterial responses to limited environments in the presence of the host. Results Analysis of intra- and extracellular changes identified 2380 proteins from the total cellular proteome (cell pellet) and 246 secreted proteins (supernatant). Specifically, HutC, a repressor of the histidine utilization operon, showed significantly increased abundance under zinc-replete conditions, which coincided with an expected reduction in expression of genes within the hut operon from our validating qRT-PCR analysis. Additionally, we characterized a putative cation transport regulator, ChaB that showed significantly higher abundance under zinc-replete vs. -limited conditions, suggesting a role in metal ion homeostasis. Phenotypic analysis of a chaB deletion strain demonstrated a reduction in capsule production, zinc-dependent growth and ion utilization, and reduced virulence when compared to the wild-type strain. Conclusions This is first study to comprehensively profile the impact of zinc availability on the proteome and secretome of K. pneumoniae and uncover a novel connection between zinc transport and capsule production in the bacterial system.

scholarly journals Metallothionein: A Multifunctional Protein from Toxicity to Cancer

2003 ◽  
Vol 18 (3) ◽  
pp. 162-169 ◽  
Author(s):  
S.E. Theocharis ◽  
A.P. Margeli ◽  
A. Koutselinis
Keyword(s):  
Cell Proliferation ◽  
Metal Ion ◽  
Defense Mechanisms ◽  
Ion Homeostasis ◽  
Low Molecular Weight ◽  
Multifunctional Protein ◽  
Metal Ion Homeostasis ◽  
Potential Marker ◽  
Proliferation And Apoptosis ◽  
Carcinogenic Process

The metallothionein (MT) family is a class of low molecular weight, intracellular and cysteine-rich proteins presenting high affinity for metal ions. Although the members of this family were discovered nearly 40 years ago, their functional significance remains obscure. Four major MT isoforms, MT-1, MT-2, MT-3 and MT-4, have been identified in mammals. MTs are involved in many pathophysiological processes such as metal ion homeostasis and detoxification, protection against oxidative damage, cell proliferation and apoptosis, chemoresistance and radiotherapy resistance. MT isoforms have been shown to be involved in several aspects of the carcinogenic process, cancer development and progression. MT expression has been implicated as a transient response to any form of stress or injury providing cytoprotective action. Although MT participates in the carcinogenic process, its use as a potential marker of tumor differentiation or cell proliferation, or as a predictor of poor prognosis remains unclear. In the present review the involvement of MT in defense mechanisms to toxicity and in carcinogenicity is discussed.

scholarly journals The novel ECF56 SigG1-RsfG system modulates morphological differentiation and metal-ion homeostasis in Streptomyces tsukubaensis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Rute Oliveira ◽  
Matthew J. Bush ◽  
Sílvia Pires ◽  
Govind Chandra ◽  
Delia Casas-Pastor ◽  
...  
Keyword(s):  
Metal Ion ◽  
Ion Homeostasis ◽  
Morphological Differentiation ◽  
The Novel ◽  
Copper Trafficking ◽  
Streptomyces Tsukubaensis ◽  
Metal Ion Homeostasis ◽  
Σ Factor ◽  
Domain Organisation

AbstractExtracytoplasmic function (ECF) sigma factors are key transcriptional regulators that prokaryotes have evolved to respond to environmental challenges. Streptomyces tsukubaensis harbours 42 ECFs to reprogram stress-responsive gene expression. Among them, SigG1 features a minimal conserved ECF σ2–σ4 architecture and an additional C-terminal extension that encodes a SnoaL_2 domain, which is characteristic for ECF σ factors of group ECF56. Although proteins with such domain organisation are widely found among Actinobacteria, the functional role of ECFs with a fused SnoaL_2 domain remains unknown. Our results show that in addition to predicted self-regulatory intramolecular amino acid interactions between the SnoaL_2 domain and the ECF core, SigG1 activity is controlled by the cognate anti-sigma protein RsfG, encoded by a co-transcribed sigG1-neighbouring gene. Characterisation of ∆sigG1 and ∆rsfG strains combined with RNA-seq and ChIP-seq experiments, suggests the involvement of SigG1 in the morphological differentiation programme of S. tsukubaensis. SigG1 regulates the expression of alanine dehydrogenase, ald and the WhiB-like regulator, wblC required for differentiation, in addition to iron and copper trafficking systems. Overall, our work establishes a model in which the activity of a σ factor of group ECF56, regulates morphogenesis and metal-ions homeostasis during development to ensure the timely progression of multicellular differentiation.

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