Biochimica et biophysica acta最新文献_第7页

Passive penetration of nitrate through the plasma membrane of Paracoccus denitrificans and its potentiation by the lipophilic tetraphenylphosphonium cation. 硝酸盐通过反硝化副球菌质膜的被动渗透及其亲脂性四苯基磷离子的强化作用。

Biochimica et biophysica acta Pub Date : 2003-03-06

Igor Kucera

{"title":"Passive penetration of nitrate through the plasma membrane of Paracoccus denitrificans and its potentiation by the lipophilic tetraphenylphosphonium cation.","authors":"Igor Kucera","doi":"","DOIUrl":"","url":null,"abstract":"Previously, it has been shown that treatment of Paracoccus denitrificans cells with phenylglyoxal inhibits the methyl-viologen-linked nitrate reductase activity by blocking the nitrate transporter. This inhibition disappears if tetraphenylphosphonium cation (TPP(+)) is added to the assay medium. In the present paper, the following evidence suggests that the effect of TPP(+) results from an increased transmembrane anion permeability and not from transporter reactivation or cell lysis. (1) Beside nitrate, TPP(+) also mediated the utilisation of chlorate, which normally lacks access to the cytoplasm. (2) The TPP(+) pathway had about hundred-times higher K(m) values for nitrate and chlorate than nitrate reductase in Triton X-100 permeabilised cells. (3) Although the uncoupler CCCP alone failed to overcome the PG block, it stimulated the operation of the TPP(+) pathway. (4) The method of continuous variations allowed the transport stoichiometry TPP(+)/NO(3)(-) to be determined as 3, indicating charge compensation for nitrate movement and the subsequent transmembrane two-electron redox reaction. Anion uptake was also measured independently from passive swelling of uncoupled spheroplasts in iso-osmotic solutions of ammonium salts. The permeability to nitrate lay in the permeability sequence Cl(-)<NO(3)(-)<ClO(4)(-)<SCN(-) and was further enhanced by TPP(+).","PeriodicalId":8811,"journal":{"name":"Biochimica et biophysica acta","volume":"1557 1-3","pages":"119-24"},"PeriodicalIF":0.0,"publicationDate":"2003-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22271313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

BBA special issue on developmental glycobiology dedicated to Roland Walter Schauer and Johannes Frederik Gerardus Vliegenthart. 关于发育糖生物学的BBA特刊，献给Roland Walter Schauer和Johannes Frederik Gerardus Vliegenthart。

Biochimica et biophysica acta Pub Date : 2002-12-19

引用次数: 0

Chemical biology of dynamic combinatorial libraries. 动态组合文库的化学生物学。

Biochimica et biophysica acta Pub Date : 2002-09-19

Olof Ramström, Taridaporn Bunyapaiboonsri, Sophie Lohmann, Jean-Marie Lehn

引用次数: 0

Cloning and promoter analysis of the cotton lipid transfer protein gene Ltp3(1). 棉花脂质转移蛋白基因 Ltp3(1) 的克隆和启动子分析。

Biochimica et biophysica acta Pub Date : 2000-08-24

H C Liu, R G Creech, J N Jenkins, D P Ma

引用次数: 0

Plasma membrane coating with cationic silica particles and osmotic shock alters the morphology of bovine aortic endothelial cells. 用阳离子二氧化硅颗粒包覆质膜和渗透冲击改变了牛主动脉内皮细胞的形态。

Biochimica et biophysica acta Pub Date : 2000-07-31

C Millot, V Le Berre-Anton, J F Tocanne, J F Tournier

引用次数: 0

Steady-state tyrosine fluorescence to study the lipid-binding properties of a wheat non-specific lipid-transfer protein (nsLTP1). 稳态酪氨酸荧光研究小麦非特异性脂质转移蛋白(nsLTP1)的脂质结合特性。

Biochimica et biophysica acta Pub Date : 2000-07-31

Douliez, Michon, Marion

{"title":"Steady-state tyrosine fluorescence to study the lipid-binding properties of a wheat non-specific lipid-transfer protein (nsLTP1).","authors":"Douliez, Michon, Marion","doi":"","DOIUrl":"","url":null,"abstract":"The binding properties of a wheat non-specific lipid-transfer protein (nsLTP1) for different mono- and diacylated lipids was investigated. Lipids varied by their chain length, unsaturation and/or polar head group. In the case of fatty acid or lysophospholipid with a C10 chain length, no interaction can be measured, while poor affinity is reported for a C12 chain length. The dissociation constant (K(d)) is about 0.5 µM independent of chain length from C14 to C18. The same affinity is obtained for C18 fatty acids with one or two unsaturations, whatever the cis-trans double bond isomery. In all cases, the number of binding sites, n, by protein ranges between 1.6 and 1.9, suggesting that two lipids can fit within the protein. omega-Hydroxy-palmitic acid, a natural monomer of cutin polymer, is found to interact with nsLTP1 with a K(d) of 1 µM and n=2. In contrast with previous data that reported the binding of the anionic diacylated phospholipid, DMPG (Sodano et al., FEBS Lett. 416 (1997) 130-134), nsLTP1 is not able to bind dimyristoylphosphatidylcholine, dimyristoylphosphatidic acid, palmitoyl-oleoylphosphatidylcholine or palmitoyl-oleoylphosphatidylglycerol added as liposomes or solubilized in ethanol. However, when both nsLTP1 and lipids are first solubilized in methanol, and then in the buffer, it was evidenced that the protein can bind these lipids. These results suggest that lipid-lipid interactions play an essential role in the binding process of plant nsLTP1 as previously mentioned for other lipid-transfer proteins.","PeriodicalId":8811,"journal":{"name":"Biochimica et biophysica acta","volume":"1467 1","pages":"65-72"},"PeriodicalIF":0.0,"publicationDate":"2000-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21836372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Plasma membrane coating with cationic silica particles and osmotic shock alters the morphology of bovine aortic endothelial cells. 用阳离子二氧化硅颗粒包覆质膜和渗透冲击改变了牛主动脉内皮细胞的形态。

Biochimica et biophysica acta Pub Date : 2000-07-31

Millot, Le Berre-Anton V, Tocanne, Tournier

引用次数: 0

Steady-state tyrosine fluorescence to study the lipid-binding properties of a wheat non-specific lipid-transfer protein (nsLTP1). 稳态酪氨酸荧光研究小麦非特异性脂质转移蛋白(nsLTP1)的脂质结合特性。

Biochimica et biophysica acta Pub Date : 2000-07-31

J P Douliez, T Michon, D Marion

{"title":"Steady-state tyrosine fluorescence to study the lipid-binding properties of a wheat non-specific lipid-transfer protein (nsLTP1).","authors":"J P Douliez, T Michon, D Marion","doi":"","DOIUrl":"","url":null,"abstract":"The binding properties of a wheat non-specific lipid-transfer protein (nsLTP1) for different mono- and diacylated lipids was investigated. Lipids varied by their chain length, unsaturation and/or polar head group. In the case of fatty acid or lysophospholipid with a C10 chain length, no interaction can be measured, while poor affinity is reported for a C12 chain length. The dissociation constant (Kd) is about 0.5 microM independent of chain length from C14 to C18. The same affinity is obtained for C18 fatty acids with one or two unsaturations, whatever the cis-trans double bond isomery. In all cases, the number of binding sites, n, by protein ranges between 1.6 and 1.9, suggesting that two lipids can fit within the protein. omega-Hydroxy-palmitic acid, a natural monomer of cutin polymer, is found to interact with nsLTP1 with a Kd of 1 microM and n = 2. In contrast with previous data that reported the binding of the anionic diacylated phospholipid, DMPG (Sodano et al., FEBS Lett. 416 (1997) 130-134), nsLTP1 is not able to bind dimyristoylphosphatidylcholine, dimyristoylphosphatidic acid, palmitoyl-oleoylphosphatidylcholine or palmitoyl-oleoylphosphatidylglycerol added as liposomes or solubilized in ethanol. However, when both nsLTP1 and lipids are first solubilized in methanol, and then in the buffer, it was evidenced that the protein can bind these lipids. These results suggest that lipid-lipid interactions play an essential role in the binding process of plant nsLTP1 as previously mentioned for other lipid-transfer proteins.","PeriodicalId":8811,"journal":{"name":"Biochimica et biophysica acta","volume":"1467 1","pages":"65-72"},"PeriodicalIF":0.0,"publicationDate":"2000-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21770152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Conformational relaxation following reduction of the photoactive bacteriopheophytin in reaction centers from Balstochloris viridis. Influence of mutations at position M208. Balstochloris viridis反应中心光活性细菌叶绿素减少后的构象松弛。M208位点突变的影响。

Biochimica et biophysica acta Pub Date : 2000-07-20

F Müh, M Bibikova, E Schlodder, D Oesterhelt, W Lubitz

{"title":"Conformational relaxation following reduction of the photoactive bacteriopheophytin in reaction centers from Balstochloris viridis. Influence of mutations at position M208.","authors":"F Müh, M Bibikova, E Schlodder, D Oesterhelt, W Lubitz","doi":"","DOIUrl":"","url":null,"abstract":"The photochemically trapped bacteriopheophytin (BPh) b radical anion in the active branch (phi(*-)A) of reaction centers (RCs) from Blastochloris (formerly called Rhodopseudomonas) viridis is characterized by 1H-ENDOR as well as optical absorption spectroscopy. The two site-directed mutants YF(M208) and YL(M208), in which tyrosine at position M208 is replaced by phenylalanine and leucine, respectively, are investigated and compared with the wild type. The residue at M208 is in close proximity to the primary electron donor, P, the monomeric bacteriochlorophyll (BCh1), B(A), and the BPh, phiA, that are involved in the transmembrane electron transfer to the quinone, Q(A), in the RC. The analysis of the ENDOR spectra of (phi(*-)A at 160 K indicates that two distinct states of phi(*-)A are present in the wild type and the mutant YF(M208). Based on a comparison with phi(*-)A in RCs of Rhodobacter sphaeroides the two states are interpreted as torsional isomers of the 3-acetyl group of phiA. Only one phi(*-)A state occurs in the mutant YL(M208). This effect of the leucine residue at position M208 is explained by steric hindrance that locks the acetyl group in one specific position. On the basis of these results, an interpretation of the optical absorption difference spectrum of the state phi(*-)AQ(*-)A is attempted. This state can be accumulated at 100 K and undergoes an irreversible change between 100 and 200 K [Tiede et al., Biochim. Biophys. Acta 892 (1987) 294-302]. The corresponding absorbance changes in the BCh1 Q(x) and Q(y) regions observed in the wild type also occur in the YF(M208) mutant but not in YL(M208). The observed changes in the wild type and YF(M208) are assigned to RCs in which the 3-acetyl group of phiA changes its orientation. It is concluded that this distinct structural relaxation of phiA can significantly affect the optical properties of B(A) and contribute to the light-induced absorption difference spectra.","PeriodicalId":8811,"journal":{"name":"Biochimica et biophysica acta","volume":"1459 1","pages":"191-201"},"PeriodicalIF":0.0,"publicationDate":"2000-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21763903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Conformational relaxation following reduction of the photoactive bacteriopheophytin in reaction centers from Blastochloris viridis. Influence of mutations at position M208. 绿芽草藻反应中心光活性菌绿素减少后的构象松弛。M208位点突变的影响。

Biochimica et biophysica acta Pub Date : 2000-07-20

Müh, Bibikova, Schlodder, Oesterhelt, Lubitz

{"title":"Conformational relaxation following reduction of the photoactive bacteriopheophytin in reaction centers from Blastochloris viridis. Influence of mutations at position M208.","authors":"Müh, Bibikova, Schlodder, Oesterhelt, Lubitz","doi":"","DOIUrl":"","url":null,"abstract":"The photochemically trapped bacteriopheophytin (BPh) b radical anion in the active branch (Phi(A)(&z.rad;-)) of reaction centers (RCs) from Blastochloris (formerly called Rhodopseudomonas) viridis is characterized by 1H-ENDOR as well as optical absorption spectroscopy. The two site-directed mutants YF(M208) and YL(M208), in which tyrosine at position M208 is replaced by phenylalanine and leucine, respectively, are investigated and compared with the wild type. The residue at M208 is in close proximity to the primary electron donor, P, the monomeric bacteriochlorophyll (BChl), B(A), and the BPh, Phi(A), that are involved in the transmembrane electron transfer to the quinone, Q(A), in the RC. The analysis of the ENDOR spectra of Phi(A)(&z.rad;-) at 160 K indicates that two distinct states of Phi(A)(&z.rad;-) are present in the wild type and the mutant YF(M208). Based on a comparison with Phi(A)(&z.rad;-) in RCs of Rhodobacter sphaeroides the two states are interpreted as torsional isomers of the 3-acetyl group of Phi(A). Only one Phi(A)(&z.rad;-) state occurs in the mutant YL(M208). This effect of the leucine residue at position M208 is explained by steric hindrance that locks the acetyl group in one specific position. On the basis of these results, an interpretation of the optical absorption difference spectrum of the state Phi(A)(&z.rad;-)Q(A)(&z.rad;-) is attempted. This state can be accumulated at 100 K and undergoes an irreversible change between 100 and 200 K [Tiede et al., Biochim. Biophys. Acta 892 (1987) 294-302]. The corresponding absorbance changes in the BChl Q(x) and Q(y) regions observed in the wild type also occur in the YF(M208) mutant but not in YL(M208). The observed changes in the wild type and YF(M208) are assigned to RCs in which the 3-acetyl group of Phi(A) changes its orientation. It is concluded that this distinct structural relaxation of Phi(A) can significantly affect the optical properties of B(A) and contribute to the light-induced absorption difference spectra.","PeriodicalId":8811,"journal":{"name":"Biochimica et biophysica acta","volume":"1459 1","pages":"191-201"},"PeriodicalIF":0.0,"publicationDate":"2000-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21837345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0