Mechanisms of Thermophily

Amelunxen, Remi E.; Murdock, Archie L.

doi:10.3109/10408417809090626

Cited by 82 publications

(31 citation statements)

References 223 publications

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“…Therefore, it seems possible that the two groups of polypeptides may have functional similarities as well. Whatever the function of the heatstable polypeptides, the results of this and previous studies (1 1,15,18,23,24) show that ABA can control synthesis of polypeptides in endosperm tissues of seeds as it does in the embryos of seeds of rape (7), French bean (34), wheat (37), rice (33), and soybean (5).…”

Section: Solubility Characteristics Of Aba-induced Polypeptidesmentioning

confidence: 88%

“…The obvious possibility is the elevated level of Glx in both protein fractions and there is evidence in the literature which supports this. Hydrogen bonding, electrostatic interactions (salt bridges), hydrophobic interactions, and disulfide bridges are important in the folding and conformational stability of proteins (1,2,4,21,28,35), but a clear understanding of the causes of heat stability of proteins does not appear to have emerged yet. However, comparisons of counterpart proteins from thermo-and mesophilic bacteria have shown that differences in only one or two amino acids, from uncharged to charged, can dramatically increase heat stability (26,27,36).…”

Section: Solubility Characteristics Of Aba-induced Polypeptidesmentioning

confidence: 99%

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Heat-Stable Proteins and Abscisic Acid Action in Barley Aleurone Cells

Jacobsen¹,

Shaw²

1989

Plant Physiol.

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ABSTRACT[35S]Methionine labeling experiments showed that abscisic acid (ABA) induced the synthesis of at least 25 polypeptides in mature barley (Hordeum vulgare) aleurone cells. The polypeptides were not secreted. Whereas most of the proteins extracted from aleurone cells were coagulated by heating to 100°C for 10 minutes, most of the ABA-induced polypeptides remained in solution (heat-stable). ABA had little effect on the spectrum of polypeptides that were synthesized and secreted by aleurone cells, and most of these secreted polypeptides were also heatstable. Coomassie blue staining of sodium dodecyl sulfate polyacrylamide gels indicated that ABA-induced polypeptides already occurred in high amounts in mature aleurone layers having accumulated during grain development. About 60% of the total protein extracted from mature aleurone was heat stable. Amino acid analyses of total preparations of heat-stable and heat-labile proteins showed that, compared to heat-labile proteins, heatstable intracellular proteins were characterized by higher glutamic acid/glutamine (Glx) and glycine levels and lower levels of neutral amino acids. Secreted heat-stable proteins were rich in Glx and proline. The possibilities that the accumulation of the heat-stable polypeptides during grain development is controlled by ABA and that the function of these polypeptides is related to their abundance and extraordinary heat stability are considered.The aleurone layer of barley has played an important role in the study of the actions of ABA and GA3 in regulating cellular processes. In this tissue, GA3 promotes and ABA inhibits the synthesis of a number of hydrolytic enzymes, in particular a-amylase, and studies of this interaction at the levels of gene transcription, mRNA ( 18). There is no evidence yet which bears on the question of whether or not ABA-induced polypeptides are related to the mechanism by which ABA antagonizes GA3 action.The object of this study was to further characterize the ABA-induced polypeptides and we focus on their heat stability (resistance to coagulation by heat). It has been found previously (17) that heat shock proteins are resistant to coagulation by heat. Because of the association of ABA with the response of plant tissues to water stress (for review see ref. 8), it seemed worthwhile to consider the possibility that ABA-induced polypeptides might also be stress-related and that they might also be resistant to coagulation by heat. This report shows that many of the ABA-induced polypeptides in barley aleurone are not coagulated by heat and using this property in a purification step, we have been able to examine the polypeptides more closely that has hitherto been possible. Our results indicate that many of the ABA-induced polypeptides are abundant, that they already exist in mature aleurone, and that they exhibit a range of solubility characteristics. MATERIALS AND METHODS Preparation and Incubation of Aleurone LayersAleurone layers were prepared from grains of Hordeum vulgare L. cv Himalaya grain grown in Pullma...

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Section: Solubility Characteristics Of Aba-induced Polypeptidesmentioning

confidence: 88%

Section: Solubility Characteristics Of Aba-induced Polypeptidesmentioning

confidence: 99%

Heat-Stable Proteins and Abscisic Acid Action in Barley Aleurone Cells

Jacobsen¹,

Shaw²

1989

Plant Physiol.

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“…Several reviews deal with the stability of proteins and other cell components at elevated temperatures [2][3][4]. Due to subtle differences in hydrogen bonding, disulfide bridges and ionic or hydrophobic interactions proteins of thermophilic microorganisms are generally more thermostable and thermoactive then those of mesophilic micro-organisms [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Application of thermostable reaction centers from Chloroflexus aurantiacus as a protonmotive force generating system

Speelmans

Hillenga

Poolman

et al. 1993

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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“…Previous studies on the structure and stability of LDH from mesophilic, psychrophilic and thermophilic sources were performed in order to elucidate traffic rules governing the gross trafficking of amino acid changes upon temperature adaptation (Amelunxen and Murdock, 1978;Argos et al, 1979;Zuber, 1988;Zulli et al, 1991). Recently, the enzyme from the hyperthermophilic bacterium Therrnotoga maritima was isolated (Wrba et al, 1990a).…”

mentioning

confidence: 99%

The l‐lactate dehydrogenase gene of the hyperthermophilic bacterium Thermotoga maritima cloned by complementation in Escherichia coli

Ostendorp

Liebl

Schurig

et al. 1993

European Journal of Biochemistry

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The gene for a l(+)‐lactate dehydrogenase from the hyperthermophilic bacterium Thermotoga maritima was cloned by complementation of an Escherichia coli pfl. ldh mutant. The gene is part of a 4.5 kb SauIIIA fragment obtained by partial digestion of the Thermotoga genome. The DNA fragment was physically mapped and the putative Shine‐Dalgarno sequence within the non‐coding region determined. The gene contains 960 bp, including the stop codon, corresponding to 319 amino acids/subunit of the homotetrameric enzyme. Part of the amino acid sequence was confirmed by Edman degradation of peptides obtained from nanomolar quantities of the purified enzyme by tryptic digestion. A comparison of the amino acid sequenc̀e with those of known prokaryotic l‐lactate dehydrogenases reveals a high similarity, especially with the enzyme from thermophilic sources, where up to 48% identity is found. The gene was expressed as an active enzyme in a heterologous host.

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Mechanisms of Thermophily

Cited by 82 publications

References 223 publications

Heat-Stable Proteins and Abscisic Acid Action in Barley Aleurone Cells

Heat-Stable Proteins and Abscisic Acid Action in Barley Aleurone Cells

Application of thermostable reaction centers from Chloroflexus aurantiacus as a protonmotive force generating system

The l‐lactate dehydrogenase gene of the hyperthermophilic bacterium Thermotoga maritima cloned by complementation in Escherichia coli

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