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[Effect of water soluble non-membrane proteins on the phospholipid structure]. [水溶性非膜蛋白对磷脂结构的影响]。

Biofizika Pub Date : 2002-03-01

G M Sorokoumova, A A Selishcheva, O P Tiurina, S G Alekseeva, O M Martynova, T V Sharf, V I Shvets

{"title":"[Effect of water soluble non-membrane proteins on the phospholipid structure].","authors":"G M Sorokoumova, A A Selishcheva, O P Tiurina, S G Alekseeva, O M Martynova, T V Sharf, V I Shvets","doi":"","DOIUrl":"","url":null,"abstract":"The interaction of water-soluble nonmembraneous proteins (trypsin and the basic pancreatic trypsin inhibitor (BPTI)) with soybean phospholipids was studied using multilamellar vesicles. Multilamellar vesicles were obtained from soybean lipid extracts and mixtures of individual phospholipids based on phosphatidylcholine. These mixtures contain different phospholipids: \"bilayer\", \"nonbilayer\", and negatively charged. It was shown that the content of both proteins in the complex depends on pH and the presence of negatively charged components. On the basis of this finding, the conclusion about the electrostatic nature of lipid-protein interaction was made. The structural organization of soybean phospholipids in multilamellar vesicles was studied in the presence and absence of the proteins using broad-line 31P-NMR spectroscopy. It was found that, in mixtures of phospholipids of complex composition, different types of phases coexist, and phospholipids of different classes can compensate the effects of each other. Trypsin and BPTI affect the structure of phospholipids in a similar way, inducing considerable structural changes in multilamellar vesicles of preparations containing negatively charged components in whose structure there coexisted primordially the bilayer and isotropic phases.","PeriodicalId":502095,"journal":{"name":"Biofizika","volume":"47 2","pages":"268-76"},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138816229","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

[Effect of high magnesium ion concentration on the electron transport rate and proton exchange in thylakoid membranes in higher plants]. [高浓度镁离子对高等植物类囊体膜电子传递速率和质子交换的影响]。

Biofizika Pub Date : 2001-11-01

A R Ignat'ev, S A Khorobrykh, B N Ivanov

{"title":"[Effect of high magnesium ion concentration on the electron transport rate and proton exchange in thylakoid membranes in higher plants].","authors":"A R Ignat'ev, S A Khorobrykh, B N Ivanov","doi":"","DOIUrl":"","url":null,"abstract":"The effects of magnesium ion concentration on the rate of electron transport in isolated pea thylakoids were investigated in the pH range from 4.0 up to 8.0. In the absence of magnesium ions in the medium and in the presence of 5 mM MgCl2 in the experiments not only without added artificial acceptors but also with ferricyanide or methylviologen as an acceptor, this rate had a well-expressed maximum at pH 5.0. It was shown that, after depression to minimal values at pH 5.5-6.5, it gradually rose with increasing pH. An increase in magnesium ion concentration up to 20 mM essentially affected the electron transfer rate: it decreased somewhat at pH 4.0-5.0 but increased at higher pH values. At this magnesium ion concentration, the maximum rate was at pH 6.0-6.5 and the minimum, at pH 7.0. Subsequent rise upon increasing pH to 8.0 was expressed more sharply. The influence of high magnesium ion concentration on the rate of electron transport was not observed in the presence of gramicidin D. It was found that without uncoupler, the changes in the electron transfer rate under the influence of magnesium ions correlated to the changes in the first-order rate constant of the proton efflux from thylakoids. It is supposed that the change in the ability of thylakoids to keep protons by the action of magnesium ions is the result of electrostatic interactions of these ions with the charges on the external surface of membranes. A possible role of regulation of the electron transport rate by magnesium ions in vivo is discussed.","PeriodicalId":502095,"journal":{"name":"Biofizika","volume":"46 6","pages":"1075-80"},"PeriodicalIF":0.0,"publicationDate":"2001-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138816228","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

[The non-contact effect of substances containing benzene rings and heterocycles on biological systems]. [含有苯环和杂环的物质对生物系统的非接触影响]。

Biofizika Pub Date : 2001-09-01

Iu P Frolov

引用次数: 0