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Charlotte Erlansonalbertsson - One of the best experts on this subject based on the ideXlab platform.
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Thylakoids reduce body fat and fat cell size by binding to dietary fat making it less available for absorption in high fat fed mice
Nutrition & Metabolism, 2017Co-Authors: Karin G Stenkula, Caroline Montelius, Evalena Stenblom, Emil Egecioglu, Charlotte ErlansonalbertssonAbstract:Dietary Thylakoids derived from spinach have beneficial effects on body fat accumulation and blood lipids as demonstrated in humans and rodents. Important mechanisms established include delayed fat digestion in the intestine, without causing steatorrhea, and increased fatty acid oxidation in intestinal cells. The objective of our study was to elucidate if increased fecal fat excretion is an important mechanism to normalize adipose tissue metabolism during high-fat feeding in mice supplemented with Thylakoids. Mice were randomized to receive HFD or thylHFD for 14 days (n = 14 for the control group and 16 for the thylakoid group). The effect of Thylakoids on body fat distribution, faecal and liver fat content, and adipose tissue metabolism was investigated following high-fat feeding. Thylakoid supplementation for 14 days caused an increased faecal fat content without compensatory eating compared to control. As a result, thylakoid treated animals had reduced fat mass depots and reduced liver fat accumulation compared to control. The size distribution of adipocytes isolated from visceral adipose tissue was narrowed and the cell size decreased. Adipocytes isolated from thylakoid-treated mice displayed a significantly increased lipogenesis, and protein expression of peroxisome proliferator-activated receptor gamma (PPARγ), down-stream target FAS, as well as transcription factor coactivators PGC1-α and LPIN-1 were upregulated in adipose tissue from thylakoid-fed mice. Together, these data suggest that thylakoid supplementation reduces body fat and fat cell size by binding to dietary fat and increasing its fecal excretion, thus reducing dietary fat available for absorption.
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supplementation by Thylakoids to a high carbohydrate meal decreases feelings of hunger elevates cck levels and prevents postprandial hypoglycaemia in overweight women
Appetite, 2013Co-Authors: Evalena Stenblom, Jens F. Rehfeld, Caroline Montelius, Karolina Ostbring, Maria Hakansson, Sofia Nilsson, Charlotte ErlansonalbertssonAbstract:Thylakoids are chlorophyll-containing membranes in chloroplasts that have been isolated from green leaves. It has been previously shown that Thylakoids supplemented with a high-fat meal can affect cholecystokinin (CCK), ghrelin, insulin and blood lipids in humans, and can act to suppress food intake and prevent body weight gain in rodents. This study investigates the addition of Thylakoids to a high carbohydrate meal and its effects upon hunger motivation and fullness, and the levels of glucose, insulin, CCK, ghrelin and tumour necrosis factor (TNF)-alpha in overweight women. Twenty moderately overweight female subjects received test meals on three different occasions; two thylakoid enriched and one control, separated by 1 week. The test meals consisted of a high carbohydrate Swedish breakfast, with or without addition of Thylakoids. Blood samples and VAS-questionnaires were evaluated over a 4-h period. Addition of Thylakoids suppressed hunger motivation and increased secretion of CCK from 180 min, and prevented postprandial hypoglycaemia from 90 min following food intake. These effects indicate that Thylakoids may intensify signals of satiety. This study therefore suggests that the dietary addition of Thylakoids could aid efforts to reduce food intake and prevent compensational eating later in the day, which may help to reduce body weight over time.
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feeding spinach Thylakoids to rats modulates the gut microbiota decreases food intake and affects the insulin response
Journal of Nutritional Science, 2013Co-Authors: Caroline Montelius, Per-Åke Albertsson, Bjorn Westrom, Nadia Osman, Siv Ahrne, Goran Molin, Charlotte ErlansonalbertssonAbstract:Thylakoid membranes derived from green leaf chloroplasts affect appetite-regulating hormones, suppress food intake, reduce blood lipids and lead to a decreased body weight in animals and human subjects. Thylakoids also decrease the intestinal in vitro uptake of methyl-glucose in the rat. The aim of this study was to investigate the effect of dietary Thylakoids on the gut microbiota composition, mainly the taxa of lactobacilli and bifidobacteria, in rats fed either a thylakoid-enriched diet or a control diet for 10 d. At the same time, a glucose-tolerance test in the same rats was also performed. Food intake was significantly decreased in the thylakoid-fed rats compared with the control-fed rats over the 10-d study. An oral glucose tolerance test after 10 d of thylakoid- or control-food intake resulted in significantly reduced plasma insulin levels in the thylakoid-fed rats compared with the control-fed rats, while no difference was observed for blood glucose levels. Analysis of gut bacteria showed a significant increase of lactobacilli on the ileal mucosa, specifically Lactobacillus reuteri, in the rats fed the thylakoid diet compared with rats fed the control diet, while faecal lactobacilli decreased. No difference in bifidobacteria between the thylakoid and control groups was found. Analyses with terminal restriction fragment length polymorphism and principal component analysis of faeces demonstrated different microbial populations in the thylakoid- and control-fed animals. These findings indicate that Thylakoids modulate the gut microbial composition, which might be important for the regulation of body weight and energy metabolism.
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pancreatic lipase colipase binds strongly to the thylakoid membrane surface
Journal of the Science of Food and Agriculture, 2013Co-Authors: Sinan Cem Emek, Hans-erik Åkerlund, Charlotte Erlansonalbertsson, Per-Åke AlbertssonAbstract:BACKGROUND: Isolated thylakoid membranes, i.e. the photosynthetic membranes of green leaves, inhibit the activity of pancreatic lipase and colipase during hydrolysis of fat in vitro. This inhibition has been demonstrated to cause reduced food intake and improved hormonal and lipid profile in vivo. One of the reasons suggested for the inhibiting effect is binding of lipase-colipase to the thylakoid membrane surface. This prompted a study of the binding of lipase and colipase to Thylakoids. RESULTS: The results showed that lipase and colipase strongly bind to the thylakoid membrane surface. The dissociation constant was determined at 1.2 × 10(-8) mol L(-1) ; binding decreased after treatment of Thylakoids with pepsin/trypsin to 1.0 × 10(-7) and to 0.6 × 10(-7) mol L(-1) after treatment with pancreatic juice. Similarly, delipidation of Thylakoids caused a decrease in binding, the dissociation constant being 2.0 × 10(-7) mol L(-1) . CONCLUSION: The binding of pancreatic lipase-colipase to the thylakoid membrane is strong and may explain the inhibition of lipase-colipase activity by Thylakoids. After treatment with proteases to mimic intestinal digestion binding is decreased, but is still high enough to explain the observed metabolic effects of Thylakoids in vivo. © 2013 Society of Chemical Industry.
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chloroplast Thylakoids reduce glucose uptake and decrease intestinal macromolecular permeability
British Journal of Nutrition, 2011Co-Authors: Caroline Montelius, Sinan Cem Emek, Per-Åke Albertsson, Bjorn Westrom, Karolina Gustafsson, Marilyn Rayner, Charlotte ErlansonalbertssonAbstract:Thylakoid membranes, derived from chloroplasts, have previously been shown to retard fat digestion and lower blood glucose levels after oral intake. The purpose of the present study was to investigate the effect of thylakoid membranes on the passage of methyl-glucose, dextran and ovalbumin over rat intestine in vitro using Ussing chambers. The results show that Thylakoids retard the passage of each of the test molecules in a dose-dependent way. The Thylakoids appear to be attached on the mucosal surface and a mechanism is suggested that the Thylakoids delay the passage of the test molecules by sterical hindrance. The present results indicate that thylakoid membranes may be useful both to control intestinal absorption of glucose and to enhance the barrier function of the intestine.
Masahiko Ikeuchi - One of the best experts on this subject based on the ideXlab platform.
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proteases are associated with a minor fucoxanthin chlorophyll a c binding protein from the diatom chaetoceros gracilis
Biochimica et Biophysica Acta, 2012Co-Authors: Ryo Nagao, Tatsuya Tomo, Eri Noguchi, Takehiro Suzuki, Akinori Okumura, Rei Narikawa, Isao Enami, Masahiko IkeuchiAbstract:Abstract We previously showed that most subunits in the oxygen-evolving photosystem II (PSII) preparation from the diatom Chaetoceros gracilis are proteolytically unstable. Here, we focused on identifying the proteases that cleave PSII subunits in thylakoid membranes. Major PSII subunits and fucoxanthin chlorophyll (Chl) a / c ‐binding proteins (FCPs) were specifically degraded in thylakoid membranes. The PSI subunits, PsaA and PsaB, were slowly degraded, and cytochrome f was barely degraded. Using zymography, proteolytic activities for three metalloproteases (116, 83, and 75 kDa) and one serine protease (156 kDa) were detected in thylakoid membranes. Two FCP fractions (FCP-A and FCP-B/C) and a photosystem fraction were separated by sucrose gradient centrifugation using dodecyl maltoside‐solubilized Thylakoids. The FCP-A fraction featured enriched Chl c compared with the bulk of FCP-B/C. Zymography revealed that 116, 83, and 94 kDa metalloproteases were mostly in the FCP-A fraction along with the 156 kDa serine protease. When solubilized Thylakoids were separated with clear-native PAGE, zymography detected only the 83 kDa metalloprotease in the FCP-A band. Because FCP-A is selectively associated with PSII, these FCP-A-associated metalloproteases and serine protease may be responsible for the proteolytic degradation of FCPs and PSII in thylakoid membranes.
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proteases are associated with a minor fucoxanthin chlorophyll a c binding protein from the diatom chaetoceros gracilis
Biochimica et Biophysica Acta, 2012Co-Authors: Ryo Nagao, Tatsuya Tomo, Eri Noguchi, Takehiro Suzuki, Akinori Okumura, Rei Narikawa, Isao Enami, Masahiko IkeuchiAbstract:Abstract We previously showed that most subunits in the oxygen-evolving photosystem II (PSII) preparation from the diatom Chaetoceros gracilis are proteolytically unstable. Here, we focused on identifying the proteases that cleave PSII subunits in thylakoid membranes. Major PSII subunits and fucoxanthin chlorophyll (Chl) a / c ‐binding proteins (FCPs) were specifically degraded in thylakoid membranes. The PSI subunits, PsaA and PsaB, were slowly degraded, and cytochrome f was barely degraded. Using zymography, proteolytic activities for three metalloproteases (116, 83, and 75 kDa) and one serine protease (156 kDa) were detected in thylakoid membranes. Two FCP fractions (FCP-A and FCP-B/C) and a photosystem fraction were separated by sucrose gradient centrifugation using dodecyl maltoside‐solubilized Thylakoids. The FCP-A fraction featured enriched Chl c compared with the bulk of FCP-B/C. Zymography revealed that 116, 83, and 94 kDa metalloproteases were mostly in the FCP-A fraction along with the 156 kDa serine protease. When solubilized Thylakoids were separated with clear-native PAGE, zymography detected only the 83 kDa metalloprotease in the FCP-A band. Because FCP-A is selectively associated with PSII, these FCP-A-associated metalloproteases and serine protease may be responsible for the proteolytic degradation of FCPs and PSII in thylakoid membranes.
Caroline Montelius - One of the best experts on this subject based on the ideXlab platform.
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Thylakoids reduce body fat and fat cell size by binding to dietary fat making it less available for absorption in high fat fed mice
Nutrition & Metabolism, 2017Co-Authors: Karin G Stenkula, Caroline Montelius, Evalena Stenblom, Emil Egecioglu, Charlotte ErlansonalbertssonAbstract:Dietary Thylakoids derived from spinach have beneficial effects on body fat accumulation and blood lipids as demonstrated in humans and rodents. Important mechanisms established include delayed fat digestion in the intestine, without causing steatorrhea, and increased fatty acid oxidation in intestinal cells. The objective of our study was to elucidate if increased fecal fat excretion is an important mechanism to normalize adipose tissue metabolism during high-fat feeding in mice supplemented with Thylakoids. Mice were randomized to receive HFD or thylHFD for 14 days (n = 14 for the control group and 16 for the thylakoid group). The effect of Thylakoids on body fat distribution, faecal and liver fat content, and adipose tissue metabolism was investigated following high-fat feeding. Thylakoid supplementation for 14 days caused an increased faecal fat content without compensatory eating compared to control. As a result, thylakoid treated animals had reduced fat mass depots and reduced liver fat accumulation compared to control. The size distribution of adipocytes isolated from visceral adipose tissue was narrowed and the cell size decreased. Adipocytes isolated from thylakoid-treated mice displayed a significantly increased lipogenesis, and protein expression of peroxisome proliferator-activated receptor gamma (PPARγ), down-stream target FAS, as well as transcription factor coactivators PGC1-α and LPIN-1 were upregulated in adipose tissue from thylakoid-fed mice. Together, these data suggest that thylakoid supplementation reduces body fat and fat cell size by binding to dietary fat and increasing its fecal excretion, thus reducing dietary fat available for absorption.
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dietary green plant Thylakoids decrease gastric emptying and gut transit promote changes in the gut microbial flora but does not cause steatorrhea
Nutrition & Metabolism, 2016Co-Authors: Evalena Stenblom, Jens F. Rehfeld, Bjorn Westrom, Caroline Linninge, Peter Bonn, Mary Farrell, Caroline MonteliusAbstract:Green-plant Thylakoids increase satiety by affecting appetite hormones such as ghrelin, cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1). The objective of this study was to investigate if Thylakoids also affect gastrointestinal (GI) passage and microbial composition. To analyse the effects on GI passage, 16 rats were gavage-fed a control or thylakoid-supplemented high-fat diet (HFD) 30 min before receiving Evans blue. Another 16 rats were fed a control HFD or thylakoid HFD for two weeks prior to the intragastric challenge with Evans blue. The amount of Evans blue in the stomach and the distance of migration in the intestines after 30 min were used as a measurement of gastric emptying and intestinal transit. These were reduced by thylakoid supplementation in the acute study, and however not significantly also after the two-week diet study. The second aim of the study was to investigate if thylakoid-supplementation affects the gut microbiota and amount of faecal fat in healthy human volunteers (n = 34) receiving thylakoid or placebo treatments for three months. Microbiota was analysed using 16S rRNA gene sequencing and qPCR, and faecal fat was extracted by dichloromethane. The total bacteria, and specifically the Bacteriodes fragilis group, were increased by thylakoid treatment versus placebo, while Thylakoids did not cause steatorrhea. Dietary supplementation with Thylakoids thus affects satiety both via appetite hormones and GI fullness, and affects the microbial composition without causing GI adverse effects such as steatorrhea. This suggests Thylakoids as a novel agent in prevention and treatment of obesity.
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supplementation by Thylakoids to a high carbohydrate meal decreases feelings of hunger elevates cck levels and prevents postprandial hypoglycaemia in overweight women
Appetite, 2013Co-Authors: Evalena Stenblom, Jens F. Rehfeld, Caroline Montelius, Karolina Ostbring, Maria Hakansson, Sofia Nilsson, Charlotte ErlansonalbertssonAbstract:Thylakoids are chlorophyll-containing membranes in chloroplasts that have been isolated from green leaves. It has been previously shown that Thylakoids supplemented with a high-fat meal can affect cholecystokinin (CCK), ghrelin, insulin and blood lipids in humans, and can act to suppress food intake and prevent body weight gain in rodents. This study investigates the addition of Thylakoids to a high carbohydrate meal and its effects upon hunger motivation and fullness, and the levels of glucose, insulin, CCK, ghrelin and tumour necrosis factor (TNF)-alpha in overweight women. Twenty moderately overweight female subjects received test meals on three different occasions; two thylakoid enriched and one control, separated by 1 week. The test meals consisted of a high carbohydrate Swedish breakfast, with or without addition of Thylakoids. Blood samples and VAS-questionnaires were evaluated over a 4-h period. Addition of Thylakoids suppressed hunger motivation and increased secretion of CCK from 180 min, and prevented postprandial hypoglycaemia from 90 min following food intake. These effects indicate that Thylakoids may intensify signals of satiety. This study therefore suggests that the dietary addition of Thylakoids could aid efforts to reduce food intake and prevent compensational eating later in the day, which may help to reduce body weight over time.
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feeding spinach Thylakoids to rats modulates the gut microbiota decreases food intake and affects the insulin response
Journal of Nutritional Science, 2013Co-Authors: Caroline Montelius, Per-Åke Albertsson, Bjorn Westrom, Nadia Osman, Siv Ahrne, Goran Molin, Charlotte ErlansonalbertssonAbstract:Thylakoid membranes derived from green leaf chloroplasts affect appetite-regulating hormones, suppress food intake, reduce blood lipids and lead to a decreased body weight in animals and human subjects. Thylakoids also decrease the intestinal in vitro uptake of methyl-glucose in the rat. The aim of this study was to investigate the effect of dietary Thylakoids on the gut microbiota composition, mainly the taxa of lactobacilli and bifidobacteria, in rats fed either a thylakoid-enriched diet or a control diet for 10 d. At the same time, a glucose-tolerance test in the same rats was also performed. Food intake was significantly decreased in the thylakoid-fed rats compared with the control-fed rats over the 10-d study. An oral glucose tolerance test after 10 d of thylakoid- or control-food intake resulted in significantly reduced plasma insulin levels in the thylakoid-fed rats compared with the control-fed rats, while no difference was observed for blood glucose levels. Analysis of gut bacteria showed a significant increase of lactobacilli on the ileal mucosa, specifically Lactobacillus reuteri, in the rats fed the thylakoid diet compared with rats fed the control diet, while faecal lactobacilli decreased. No difference in bifidobacteria between the thylakoid and control groups was found. Analyses with terminal restriction fragment length polymorphism and principal component analysis of faeces demonstrated different microbial populations in the thylakoid- and control-fed animals. These findings indicate that Thylakoids modulate the gut microbial composition, which might be important for the regulation of body weight and energy metabolism.
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chloroplast Thylakoids reduce glucose uptake and decrease intestinal macromolecular permeability
British Journal of Nutrition, 2011Co-Authors: Caroline Montelius, Sinan Cem Emek, Per-Åke Albertsson, Bjorn Westrom, Karolina Gustafsson, Marilyn Rayner, Charlotte ErlansonalbertssonAbstract:Thylakoid membranes, derived from chloroplasts, have previously been shown to retard fat digestion and lower blood glucose levels after oral intake. The purpose of the present study was to investigate the effect of thylakoid membranes on the passage of methyl-glucose, dextran and ovalbumin over rat intestine in vitro using Ussing chambers. The results show that Thylakoids retard the passage of each of the test molecules in a dose-dependent way. The Thylakoids appear to be attached on the mucosal surface and a mechanism is suggested that the Thylakoids delay the passage of the test molecules by sterical hindrance. The present results indicate that thylakoid membranes may be useful both to control intestinal absorption of glucose and to enhance the barrier function of the intestine.
Tatsuya Tomo - One of the best experts on this subject based on the ideXlab platform.
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proteases are associated with a minor fucoxanthin chlorophyll a c binding protein from the diatom chaetoceros gracilis
Biochimica et Biophysica Acta, 2012Co-Authors: Ryo Nagao, Tatsuya Tomo, Eri Noguchi, Takehiro Suzuki, Akinori Okumura, Rei Narikawa, Isao Enami, Masahiko IkeuchiAbstract:Abstract We previously showed that most subunits in the oxygen-evolving photosystem II (PSII) preparation from the diatom Chaetoceros gracilis are proteolytically unstable. Here, we focused on identifying the proteases that cleave PSII subunits in thylakoid membranes. Major PSII subunits and fucoxanthin chlorophyll (Chl) a / c ‐binding proteins (FCPs) were specifically degraded in thylakoid membranes. The PSI subunits, PsaA and PsaB, were slowly degraded, and cytochrome f was barely degraded. Using zymography, proteolytic activities for three metalloproteases (116, 83, and 75 kDa) and one serine protease (156 kDa) were detected in thylakoid membranes. Two FCP fractions (FCP-A and FCP-B/C) and a photosystem fraction were separated by sucrose gradient centrifugation using dodecyl maltoside‐solubilized Thylakoids. The FCP-A fraction featured enriched Chl c compared with the bulk of FCP-B/C. Zymography revealed that 116, 83, and 94 kDa metalloproteases were mostly in the FCP-A fraction along with the 156 kDa serine protease. When solubilized Thylakoids were separated with clear-native PAGE, zymography detected only the 83 kDa metalloprotease in the FCP-A band. Because FCP-A is selectively associated with PSII, these FCP-A-associated metalloproteases and serine protease may be responsible for the proteolytic degradation of FCPs and PSII in thylakoid membranes.
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proteases are associated with a minor fucoxanthin chlorophyll a c binding protein from the diatom chaetoceros gracilis
Biochimica et Biophysica Acta, 2012Co-Authors: Ryo Nagao, Tatsuya Tomo, Eri Noguchi, Takehiro Suzuki, Akinori Okumura, Rei Narikawa, Isao Enami, Masahiko IkeuchiAbstract:Abstract We previously showed that most subunits in the oxygen-evolving photosystem II (PSII) preparation from the diatom Chaetoceros gracilis are proteolytically unstable. Here, we focused on identifying the proteases that cleave PSII subunits in thylakoid membranes. Major PSII subunits and fucoxanthin chlorophyll (Chl) a / c ‐binding proteins (FCPs) were specifically degraded in thylakoid membranes. The PSI subunits, PsaA and PsaB, were slowly degraded, and cytochrome f was barely degraded. Using zymography, proteolytic activities for three metalloproteases (116, 83, and 75 kDa) and one serine protease (156 kDa) were detected in thylakoid membranes. Two FCP fractions (FCP-A and FCP-B/C) and a photosystem fraction were separated by sucrose gradient centrifugation using dodecyl maltoside‐solubilized Thylakoids. The FCP-A fraction featured enriched Chl c compared with the bulk of FCP-B/C. Zymography revealed that 116, 83, and 94 kDa metalloproteases were mostly in the FCP-A fraction along with the 156 kDa serine protease. When solubilized Thylakoids were separated with clear-native PAGE, zymography detected only the 83 kDa metalloprotease in the FCP-A band. Because FCP-A is selectively associated with PSII, these FCP-A-associated metalloproteases and serine protease may be responsible for the proteolytic degradation of FCPs and PSII in thylakoid membranes.
Rei Narikawa - One of the best experts on this subject based on the ideXlab platform.
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proteases are associated with a minor fucoxanthin chlorophyll a c binding protein from the diatom chaetoceros gracilis
Biochimica et Biophysica Acta, 2012Co-Authors: Ryo Nagao, Tatsuya Tomo, Eri Noguchi, Takehiro Suzuki, Akinori Okumura, Rei Narikawa, Isao Enami, Masahiko IkeuchiAbstract:Abstract We previously showed that most subunits in the oxygen-evolving photosystem II (PSII) preparation from the diatom Chaetoceros gracilis are proteolytically unstable. Here, we focused on identifying the proteases that cleave PSII subunits in thylakoid membranes. Major PSII subunits and fucoxanthin chlorophyll (Chl) a / c ‐binding proteins (FCPs) were specifically degraded in thylakoid membranes. The PSI subunits, PsaA and PsaB, were slowly degraded, and cytochrome f was barely degraded. Using zymography, proteolytic activities for three metalloproteases (116, 83, and 75 kDa) and one serine protease (156 kDa) were detected in thylakoid membranes. Two FCP fractions (FCP-A and FCP-B/C) and a photosystem fraction were separated by sucrose gradient centrifugation using dodecyl maltoside‐solubilized Thylakoids. The FCP-A fraction featured enriched Chl c compared with the bulk of FCP-B/C. Zymography revealed that 116, 83, and 94 kDa metalloproteases were mostly in the FCP-A fraction along with the 156 kDa serine protease. When solubilized Thylakoids were separated with clear-native PAGE, zymography detected only the 83 kDa metalloprotease in the FCP-A band. Because FCP-A is selectively associated with PSII, these FCP-A-associated metalloproteases and serine protease may be responsible for the proteolytic degradation of FCPs and PSII in thylakoid membranes.
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proteases are associated with a minor fucoxanthin chlorophyll a c binding protein from the diatom chaetoceros gracilis
Biochimica et Biophysica Acta, 2012Co-Authors: Ryo Nagao, Tatsuya Tomo, Eri Noguchi, Takehiro Suzuki, Akinori Okumura, Rei Narikawa, Isao Enami, Masahiko IkeuchiAbstract:Abstract We previously showed that most subunits in the oxygen-evolving photosystem II (PSII) preparation from the diatom Chaetoceros gracilis are proteolytically unstable. Here, we focused on identifying the proteases that cleave PSII subunits in thylakoid membranes. Major PSII subunits and fucoxanthin chlorophyll (Chl) a / c ‐binding proteins (FCPs) were specifically degraded in thylakoid membranes. The PSI subunits, PsaA and PsaB, were slowly degraded, and cytochrome f was barely degraded. Using zymography, proteolytic activities for three metalloproteases (116, 83, and 75 kDa) and one serine protease (156 kDa) were detected in thylakoid membranes. Two FCP fractions (FCP-A and FCP-B/C) and a photosystem fraction were separated by sucrose gradient centrifugation using dodecyl maltoside‐solubilized Thylakoids. The FCP-A fraction featured enriched Chl c compared with the bulk of FCP-B/C. Zymography revealed that 116, 83, and 94 kDa metalloproteases were mostly in the FCP-A fraction along with the 156 kDa serine protease. When solubilized Thylakoids were separated with clear-native PAGE, zymography detected only the 83 kDa metalloprotease in the FCP-A band. Because FCP-A is selectively associated with PSII, these FCP-A-associated metalloproteases and serine protease may be responsible for the proteolytic degradation of FCPs and PSII in thylakoid membranes.
