Effects of COR6.6 and COR15am Polypeptides Encoded by COR (Cold-Regulated) Genes of Arabidopsis thaliana on the Freeze-Induced Fusion and Leakage of Liposomes

Uemura, Matsuo; Gilmour, Sarah J.; Thomashow, Michael F.; Steponkus, Peter L.

doi:10.1104/pp.111.1.313

Cited by 42 publications

(23 citation statements)

References 30 publications

(38 reference statements)

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“…This incubation produced no changes in the CD spectrum of rGmD-19 (data not shown), suggesting that the protein is unable to interact with zwitterionic phospholipid membranes. This result is in agreement with previous studies showing the lack of a specific phospholipid-protein interaction of other coldinduced proteins (Uemura et al, 1996;Webb et al, 1996). Although these results cannot discount the possibility that this group 1 LEA protein may interact with and be influenced by interaction with membrane lipids in vivo, we suggest that such interactions are unlikely given the extremely hydrophilic nature of this protein.…”

Section: Table I Secondary Structure Fractions Of Rgmd-19supporting

confidence: 81%

Temperature-Induced Extended Helix/Random Coil Transitions in a Group 1 Late Embryogenesis-Abundant Protein from Soybean

et al. 2002

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Group 1 late embryogenesis-abundant (LEA) proteins are a subset of hydrophilins that are postulated to play important roles in protecting plant macromolecules from damage during freezing, desiccation, or osmotic stress. To better understand the putative functional roles of group 1 LEA proteins, we analyzed the structure of a group 1 LEA protein from soybean (Glycine max). Differential scanning calorimetry of the purified, recombinant protein demonstrated that the protein assumed a largely unstructured state in solution. In the presence of trifluoroethanol (50% [w/v]), the protein acquired a 30% ␣-helical content, indicating that the polypeptide is highly restricted to adopt ␣-helical structures. In the presence of sodium dodecyl sulfate (1% [w/v]), 8% of the polypeptide chain adopted an ␣-helical structure. However, incubation with phospholipids showed no effect on the protein structure. Ultraviolet absorption and circular dichroism spectroscopy revealed that the protein existed in equilibrium between two conformational states. Ultraviolet absorption spectroscopy studies also showed that the protein became more hydrated upon heating. Furthermore, circular dichroism spectral measurements indicated that a minimum of 14% of amino acid residues existed in a solvent-exposed, left-handed extended helical or poly (l-proline)-type (PII) conformation at 20°C with the remainder of the protein being unstructured. The content of PII-like structure increased as temperature was lowered. We hypothesize that by favoring the adoption of PII structure, instead of the formation of ␣-helical or ␤-sheet structures, group 1 LEA proteins retain a high content of surface area available for interaction with the solvent. This feature could constitute the basis of a potential role of LEA proteins in preventing freezing, desiccation, or osmotic stress damage.Late embryogenesis-abundant (LEA) proteins accumulate to high concentrations in plant embryos during the latter stages of seed development before desiccation (Baker et al., 1988;Dure et al., 1989;Hughes and Galau, 1989). LEA proteins also accumulate in vegetative tissues exposed to exogenous abscisic acid, as well as dehydration, osmotic, and lowtemperature stress (Chandler and Robertson, 1994;Ingram and Bartels, 1996; Bray, 1997; Close, 1996 Close, , 1997Thomashow, 1998; Nylander et al., 2001). More than seven different groups of LEA proteins have been described and categorized by virtue of similarities in their deduced amino acid sequences (Baker et al., 1988;Dure et al., 1989). The majority of LEA proteins are highly hydrophilic and display a preponderance (e.g. Ala, Gly, Glu, and Thr) or lack (e.g. Trp and Cys) of certain amino acid residues (Dure, 1993a(Dure, , 1993b(Dure, , 1997. Thus, LEA proteins are part of a larger, evolutionarily conserved group of hydrophilic proteins termed "hydrophilins" involved in various adaptive responses to hyperosmotic conditions (Garay-Arroyo et al., 2000).Various functions have been proposed for different groups of LEA proteins ranging from wa...

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Section: Table I Secondary Structure Fractions Of Rgmd-19supporting

confidence: 81%

Temperature-Induced Extended Helix/Random Coil Transitions in a Group 1 Late Embryogenesis-Abundant Protein from Soybean

et al. 2002

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“…For instance, Lin and Thomashow (35) reported that the unprocessed COR15a polypeptide is effective in decreasing the incidence of freeze-induced inactivation of lactate dehydrogenase in vitro, but subsequent studies indicate that the cryoprotective effect of COR15am on lactate dehydrogenase is no greater than that of bovine serum albumin (S.J.G., unpublished data). Uemura et al (36) have found that COR15am decreases the incidence of freeze-induced fusion of liposomes frozen in vitro. However, this effect only occurs under unusual conditions-when the liposomes are frozen in dilute buffer in the absence of any solutes.…”

Section: Discussionmentioning

confidence: 99%

Constitutive expression of the cold-regulated Arabidopsis thaliana COR15a gene affects both chloroplast and protoplast freezing tolerance

Artus

Uemura

Steponkus

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

366

241

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Cold acclimation in plants is associated with the expression of COR (cold-regulated) genes that encode polypeptides of unknown function. It has been widely speculated that products of these genes might have roles in freezing tolerance. Here we provide direct evidence in support of this hypothesis. We show that constitutive expression of COR15a, a cold-regulated gene of Arabidopsis thaliana that encodes a chloroplast-targeted polypeptide, enhances the in vivo freezing tolerance of chloroplasts in nonacclimated plants by almost 2؇C, nearly one-third of the increase that occurs upon cold acclimation of wild-type plants. Significantly, constitutive expression of COR15a also affects the in vitro freezing tolerance of protoplasts. At temperatures between ؊5 and ؊8؇C, the survival of protoplasts isolated from leaves of nonacclimated transgenic plants expressing COR15a was greater than that of protoplasts isolated from leaves of nonacclimated wild-type plants. At temperatures between ؊2 and ؊4؇C, constitutive expression of COR15a had a slight negative effect on survival. The implications of these data regarding possible modes of COR15a action are discussed.

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“…CAregulated genes have been identified from numerous plant species including winter wheat (4 -6), barley (7,8), alfalfa (9 -11), and Arabidopsis (12)(13)(14). Positive correlations of coldinduced genes and freezing tolerance have been observed (10,15), and functions related to cold acclimation have been suggested for several genes (16,17).…”

mentioning

confidence: 99%

A Cold-regulated Nucleic Acid-binding Protein of Winter Wheat Shares a Domain with Bacterial Cold Shock Proteins

Karlson

Nakaminami

Toyomasu

et al. 2002

Journal of Biological Chemistry

144

154

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The molecular mechanisms of cold acclimation are still largely unknown; however, it has been established that overwintering plants such as winter wheat increases freeze tolerance during cold treatments. In prokaryotes, cold shock proteins are induced by temperature downshifts and have been proposed to function as RNA chaperones. A wheat cDNA encoding a putative nucleic acid-binding protein, WCSP1, was isolated and found to be homologous to the predominant CspA of Escherichia coli. The putative WCSP1 protein contains a three-domain structure consisting of an N-terminal cold shock domain with two internal conserved consensus RNA binding domains and an internal glycine-rich region, which is interspersed with three C-terminal CX 2 CX 4 HX 4 C (CCHC) zinc fingers. Each domain has been described independently within several nucleotide-binding proteins. Northern and Western blot analyses showed that WCSP1 mRNA and protein levels steadily increased during cold acclimation, respectively. WCSP1 induction was cold-specific because neither abscisic acid treatment, drought, salinity, nor heat stress induced WCSP1 expression. Nucleotide binding assays determined that WCSP1 binds ssDNA, dsDNA, and RNA homopolymers. The capacity to bind dsDNA was nearly eliminated in a mutant protein lacking C-terminal zinc fingers. Structural and expression similarities to E. coli CspA suggest that WCSP1 may be involved in gene regulation during cold acclimation.

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Effects of COR6.6 and COR15am Polypeptides Encoded by COR (Cold-Regulated) Genes of Arabidopsis thaliana on the Freeze-Induced Fusion and Leakage of Liposomes

Cited by 42 publications

References 30 publications

Temperature-Induced Extended Helix/Random Coil Transitions in a Group 1 Late Embryogenesis-Abundant Protein from Soybean

Temperature-Induced Extended Helix/Random Coil Transitions in a Group 1 Late Embryogenesis-Abundant Protein from Soybean

Constitutive expression of the cold-regulated Arabidopsis thaliana COR15a gene affects both chloroplast and protoplast freezing tolerance

A Cold-regulated Nucleic Acid-binding Protein of Winter Wheat Shares a Domain with Bacterial Cold Shock Proteins

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