Thiol Groups of Biological Importance

Barrón, E. S. Guzmán

doi:10.1002/9780470122563.ch4

Cited by 117 publications

(21 citation statements)

References 207 publications

(18 reference statements)

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“…The interaction between TstR and P tstR was not modified by other sulphur-related compounds including sulphate or thiosulphate. The observation that TstR activity is not affected by all reducing agents has previously been reported (for a review see Barron, 2006). Some factors that contribute to this variability are the amount and location of freely reacting -SH groups, as well as the redox potential of each compound.…”

Section: In Vitro Tstr Binding Is Modulated By Sulphite and Ferric Ironmentioning

confidence: 80%

A dual role of the transcriptional regulator TstR provides insights into cyanide detoxification in Lactobacillus brevis

Pagliai

Murdoch

Brown

et al. 2014

Molecular Microbiology

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Summary In this study we uncover two genes in Lactobacillus brevis ATCC367, tstT and tstR, encoding for a rhodanese and a transcriptional regulator involved in cyanide detoxification. TstT (LVIS_0852) belongs to a new class of thiosulfate:cyanide sulfurtransferases. We found that TstR (LVIS_0853) modulates both the expression and the activity of the downstream-encoded tstT. The TstR binding site was identified at −1 to +33, from tstR transcriptional start site. EMSA revealed that sulfite, a product of the reaction catalyzed by TstT, improved the interaction between TstR:PtstR, while Fe(III) disrupted this interaction. Site-directed mutagenesis in TstR identified M64 as a key residue in sulfite recognition, while residues H136-H139-C167-M171 formed a pocket for ferric iron coordination. In addition to its role as a transcriptional repressor, TstR is also involved in regulating the thiosulfate:cyanide sulfurtransferase activity of TstT. A 3-fold increase in TstT activity was observed in the presence of TstR, which was enhanced by the addition of Fe(III). Overexpression of the tstRT operon was found to increase the cyanide tolerance of L. brevis and Escherichia coli. The protein-protein interaction between TstR and TstT described herein represents a novel mechanism for regulation of enzymatic activity by a transcriptional regulator.

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Section: In Vitro Tstr Binding Is Modulated By Sulphite and Ferric Ironmentioning

confidence: 80%

A dual role of the transcriptional regulator TstR provides insights into cyanide detoxification in Lactobacillus brevis

Pagliai

Murdoch

Brown

et al. 2014

Molecular Microbiology

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“…The hyperactive soluble thiols such as glutathione and cysteine regulate cell respiration, act as binding posts between proteins and prosthetic groups, and support the electron transfer system (Barron 1951). In higher plants, thiol/disulphide exchange involving the glutathione pool regulates signal transduction during environmental stress (Foyer et al 1997).…”

Section: Thiol Biosynthesismentioning

confidence: 99%

“…Thiols participate in multifarious reactions in the cell ranging from electron transfer (Barron 1951) to signal transduction during environmental stress (Foyer et al 1997). In this context, glutathione has been studied in Nostoc muscorum (Fahey et al 1978), Synechococcus 6311 and Nostoc muscorum 7119 (Tel-Or et al 1985).…”

Section: Introductionmentioning

confidence: 99%

A comparison of proline, thiol levels and GAPDH activity in cyanobacteria of different origins facing temperature-stress

Singh

Asthana

Kayastha

et al. 2005

World J Microbiol Biotechnol

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Three cyanobacterial strains originating from different habitats were subjected to temperature shift exposures and monitored for levels of proline, thiol and activity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Thermophile Mastigocladus laminosus (growth optimum, 40°C), raised the proline level 4.2-fold at low temperature (20°C), for the psychrophile Nostoc 593 (growth optimum, 20°C), it was raised 8-fold at 40°C while in the mesophile Nostoc muscorum (growth optimum, 30°C), the imino acid level increased 2.3-fold during temperature 'shiftdown' to 20°C or 3.5-fold in sets facing 'shiftup' (40°C). Alterations in thiol levels in the above strains were in line with proline. It is suggested that such fluctuations reflect metabolic shifts as a response to stress. Interestingly, GAPDH activity was maximum at the respective growth temperature optimum of M. laminosus (122 nmol NADPH oxidized min )1 mg )1 protein) and Nostoc 593 (141 nmol NADPH oxidized min )1 mg )1 protein) while in N. muscorum, it increased at 40°C (101 nmol NADPH oxidized min )1 mg )1 protein) and to 93.3 nmol NADPH oxidized min )1 mg )1 protein (20°C) relative to 86 nmol NADPH oxidized min )1 mg )1 protein at 30°C. It seems that extremophiles maintain the GAPDH activity/level during growth at their respective temperatures optimal while the mesophile increases it in order to cope up with temperature-stress.

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“…Several enzymes are known to be dependent on thiol groups for their action (Barron 1951) such that if the thiol group is blocked, the enzyme activity is abolished. Many substances are known which combine with thiol groups, and their mechanisms of combination are also well known.…”

Section: Discussionmentioning

confidence: 99%

“…E. coli suspended in the solution to be investieated 1 ml in a 57" C water bath I for 5 min. The influence of mercuric chloride on sonic lysis and INT reduction was first tested since mercuric ions are known to combine with sulfhydryl groups which are essential for the activity of many enzymes ( Barron 1951). Mercuric chloride inhibited sonic lysis, but the solutions of mercuric chloride initially were acid and difficult to buffer.…”

Section: A T E R I a L S A N D M E T H O D S A Cultivation O F Tesmentioning

confidence: 99%

Disintegration by Freeze‐pressing

Edebo

1961

Acta Pathologica Microbiologica Scandinavica

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Thiol Groups of Biological Importance

Cited by 117 publications

References 207 publications

A dual role of the transcriptional regulator TstR provides insights into cyanide detoxification in Lactobacillus brevis

A dual role of the transcriptional regulator TstR provides insights into cyanide detoxification in Lactobacillus brevis

A comparison of proline, thiol levels and GAPDH activity in cyanobacteria of different origins facing temperature-stress

Disintegration by Freeze‐pressing

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