Proteomic characterization of acid stress response inSynechocystis sp. PCC 6803

Kurian, Dominic; Phadwal, Kanchan; Mäenpää, Pekka H.

doi:10.1002/pmic.200600033

Cited by 75 publications

(55 citation statements)

References 48 publications

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“…This complements earlier findings concerning acid-stress response, which revealed several mechanisms enabling various microorganisms to survive under low pH in laboratory conditions (Kallas & Castenholz, 1982;Foster & Hall, 1991;Huang et al, 2002;Kurian et al, 2006). Among them are analyses of Synechocystis 6308, a strain isolated from Lake Wisconsin, which turned out to be able to respond to and survive the acid stress by increasing the pH in culture (Huang et al, 2002).…”

Section: Discussionsupporting

confidence: 71%

Do acid-tolerant picocyanobacteria exist? A study of two strains isolated from humic lakes in Poland

2013

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The occurrence of picocyanobacteria, the smallest cell-size fraction of cyanobacteria, in low-pH waters, is still poorly studied. In this study, we tested the hypothesis that picocyanobacteria found occasionally in low-pH environments are adapted to such water conditions. We isolated picocyanobacteria by means of the cytometric method from two humic lakes with pH B5. We obtained two strains belonging to two cosmopolitan phylogenetic clades of picocyanobacteria: Cyanobium gracile cluster and Subalpine cluster I. Experiments on filtered lake water from low-pH (B5) and slightly alkaline (pH 8.2) lakes, and with an acidified cyanobacterium medium (pH 4.5) were conducted to test the growth of the isolated picocyanobacteria in various pH conditions. The experimental results of this study showed that some picocyanobacteria strains were acid tolerant, achieving higher growth rates and reaching higher maximum numbers in humic, naturally acidic waters rather than in alkaline waters. We show that despite a close phylogenetic relationship, strains of picocyanobacteria exhibit significant physiological and ecological diversity and that at least some picocyanobacteria have the evolutionary potential to cope with low pH. Characterization of the genetic basis of acid tolerance in picocyanobacteria is important to understand how these microorganisms function in aquatic ecosystems and how their communities may respond to a changing environment.

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Section: Discussionsupporting

confidence: 71%

Do acid-tolerant picocyanobacteria exist? A study of two strains isolated from humic lakes in Poland

2013

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“…The positive effect of increasing pH on the proteolytic activity of HhoA correlated well with the pH tolerance of Synechocystis sp. strain PCC 6803 cells, which are able to survive under slightly acidic conditions but prefer alkaline conditions for growth, and thus with the pH experienced in the periplasm (24). In contrast, A. thaliana Deg1 was most active at a low pH, pH 6.0, and the activity decreased at a higher pH, which corresponds to the conditions prevalent in the thylakoid lumen (6).…”

Section: Discussionmentioning

confidence: 92%

The Serine Protease HhoA from Synechocystis sp. Strain PCC 6803: Substrate Specificity and Formation of a Hexameric Complex Are Regulated by the PDZ Domain

2007

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Enzymes of the ATP-independent Deg serine endopeptidase family are very flexible with regard to their substrate specificity. Some family members cleave only one substrate, while others act as general proteases on unfolded substrates. The proteolytic activity of Deg proteases is regulated by PDZ protein interaction domains. Here we characterized the HhoA protease from Synechocystis sp. strain PCC 6803 in vitro using several recombinant protein constructs. The proteolytic activity of HhoA was found to increase with temperature and basic pH and was stimulated by the addition of Mg 2؉ or Ca 2؉ . We found that the single PDZ domain of HhoA played a critical role in regulating protease activity and in the assembly of a hexameric complex. Deletion of the PDZ domain strongly reduced proteolysis of a sterically challenging resorufin-labeled casein substrate, but unlabeled ␤-casein was still degraded. Reconstitution of the purified HhoA with total membrane proteins isolated from Synechocystis sp. wild-type strain PCC 6803 and a ⌬hhoA mutant resulted in specific degradation of selected proteins at elevated temperatures. We concluded that a single PDZ domain of HhoA plays a critical role in defining the protease activity and oligomerization state, combining the functions that are attributed to two PDZ domains in the homologous DegP protease from Escherichia coli. Based on this first enzymatic study of a Deg protease from cyanobacteria, we propose a general role for HhoA in the quality control of extracytoplasmic proteins, including membrane proteins, in Synechocystis sp. strain PCC 6803.Proteolysis is an essential process in every living cell and is involved in protein quality control (45), as well as in regulation of diverse cellular events (11). In the cyanobacterium Synechocystis sp. strain PCC 6803, which is a widely used model system for studying photosynthesis and acclimation to abiotic stresses, 77 proteases are encoded in the genome (http://merops.sanger .ac.uk/). Three genes encode ATP-independent serine endopeptidases belonging to the Deg (HtrA) family (14,19,21,40). The protease domain of these enzymes harbors the hallmark catalytic triad consisting of His, Asp, and Ser responsible for the proteolytic activity and may additionally confer a chaperone function (16,42). Deg proteases usually contain one or two protein-protein interaction domains of the PDZ type C terminal of the protease domain (7). Studies of Escherichia coli DegP (also designated HtrA), E. coli DegS (also designated HhoB), and human HtrA2 showed that PDZ domains regulate the proteolytic activity (16,18,27,38,42,46), are involved in the formation of homooligomeric complexes (16,18,38), and play a role in substrate recognition (7,16,23,35).In prokaryotes, Deg proteases are usually located in the periplasm and are implicated in the response to a variety of stresses, such as heat (3, 30, 33), oxidative stress (3, 47), and high-light stress (3, 39). Deg proteases are also essential for virulence in several pathogenic bacteria (33,47). An intriguing fea...

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“…A previous proteomic analysis using Synechocystis sp. strain PCC 6803 showed that its OxdC homolog was induced and secreted into the periplasm when cells were grown under acidic conditions (20). The mechanisms linking induction of OxdC to growth under low-pH conditions are not yet clear but likely involve YvrL.…”

Section: Discussionmentioning

confidence: 99%

The YvrI Alternative σ Factor Is Essential for Acid Stress Induction of Oxalate Decarboxylase in Bacillus subtilis

2009

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YvrI is a recently identified alternative factor in Bacillus subtilis that requires the coactivator YvrHa to activate transcription. Previously, a strain engineered to overproduce YvrI was found to overproduce oxalate decarboxylase (OxdC), and further analysis identified three YvrI-activated promoters preceding the yvrI-yvrHa, yvrJ, and oxdC-yvrL operons. Independently, proteome analyses identified OxdC as a highly abundant, cell wall-associated protein that accumulated under acidic growth conditions. We show here that the accumulation of OxdC in the cell wall proteome under acidic growth conditions is absolutely dependent on YvrI and is correlated with enhanced transcription of both the yvrI-yvrHa and the oxdC-yvrL operons. Conversely, OxdC accumulates to a high level even under nonacidic growth conditions in cells lacking YvrL, a negative regulator of YvrI/YvrHa-dependent transcription. These results indicate that YvrI and its associated coregulators YvrHa and YvrL are required for the regulation of OxdC expression by acid stress. The high-level accumulation of OxdC depends, in part, on a strong oxdC promoter. A regulatory sequence with similarity to an upstream promoter element (UP) was identified upstream of the oxdC promoter and is required for high-level promoter activity. Conservation of the YvrI/YvrHa/YvrL regulatory system among related species allowed us to deduce an expanded consensus sequence for the compositionally unusual promoters recognized by this new factor.

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Proteomic characterization of acid stress response inSynechocystis sp. PCC 6803

Cited by 75 publications

References 48 publications

Do acid-tolerant picocyanobacteria exist? A study of two strains isolated from humic lakes in Poland

Do acid-tolerant picocyanobacteria exist? A study of two strains isolated from humic lakes in Poland

The Serine Protease HhoA from Synechocystis sp. Strain PCC 6803: Substrate Specificity and Formation of a Hexameric Complex Are Regulated by the PDZ Domain

The YvrI Alternative σ Factor Is Essential for Acid Stress Induction of Oxalate Decarboxylase in Bacillus subtilis

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