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1999 (2)
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1Author    L. Ya, E. W. Baranov, SchlagRequires cookie*
 Title    New Mechanism for Facile Charge Transport in Polypeptides  
 Abstract    An electronic hole migration accross a polypeptide chain is discussed with special reference to new ab initio computational results and to the experimental observations of Weinkauf et al. on the charge photoinjection into the polypeptide backbone. New mechanistic details for this efficient charge transport process are proposed. The process is viewed as a vibronically induced hole hopping between local aminoacid sites driven by large amplitude torsional motions of the floppy backbone. 
  Reference    Z. Naturforsch. 54a, 387—396 (1999); received May 7 1999 
  Published    1999 
  Keywords    Protein, Polypeptide, Charge Transfer, Hopping 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0387.pdf 
 Identifier    ZNA-1999-54a-0387 
 Volume    54 
2Author    Wilhelm Menke, Alfons Radunz, GeorgH. Schmid, Friederike Koenig, Rolf-Dieter HirtzRequires cookie*
 Title    Intermolecular Interactions of Polypeptides and Lipids in the Thylakoid Membrane  
 Abstract    Intermolecular interactions between chloroplast lipids and a polypeptide fraction from thylakoids were investigated by far ultraviolet circular dichroism. The polypeptide fraction was isolated from dodecyl sulfate-containing buffers. It exhibits an average molecular weight of 24 000. The circular dichroism of this polypeptide fraction measured as mean residue ellipticity is greater in the presence of sodium dodecyl sulfate than in the absence of this detergent. This effect is reversible. Addition of sulfoquinovosyl diglyceride to the dodecyl sulfate-free solution of the polypeptide also causes an increase of the circular dichroism. This increase was only observed in the pH-range between 6.9 and 7.4. The effect of dodecyl sulfate or sulfolipid on the circular dichroism is inter­ preted to indicate an increase of a-helix content. Monogalactosyl diglyceride, digalactosyl di­ glyceride and phosphatidyl glycerol gave no reaction. The attempt to obtain a conformational analysis of the polypeptide in the different states did not yield an entirely satisfactory result. Anti­ sera to sulfolipid inhibit photosynthetic electron transport of stroma-freed chloroplasts in the region of light reaction I. This inhibition is restricted to the same pH-range as the non-covalent binding of sulfolipid to the polypeptides. It appears that in the cell membrane-bound metabolic processes are regulated by this pH-dependence of the sulfolipid-polypetide interactions. 
  Reference    (Z. Naturforsch. 31c, 436 [1976]; received April 30 1976) 
  Published    1976 
  Keywords    Interactions, Polypeptides, Lipids, Thylakoid Membrane, Photosynthesis 
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 TEI-XML for    default:Reihe_C/31/ZNC-1976-31c-0436.pdf 
 Identifier    ZNC-1976-31c-0436 
 Volume    31 
3Author    Grzegorz JackowskiRequires cookie*
 Title    Senescence-Related Changes in the Subcomplex Arrangement of the Major Light-Harvesting Chlorophyll a/b-Protein Complex of Photosystem II (LHCII) as Influenced by Cytokinin  
 Abstract    The major light-harvesting chlorophyll a /b -protein complex of photosystem II (LHCII) from fresh barley leaves could be resolved by non-denaturing IEF into five trimeric subcom­ plexes designated 1 -5 in order of decrasing pi value. IEF-based analysis of PSII particles isolated from leaves in which the processes of senescence were induced by detachement and dark-incubation in the presence of water for 0 -8 days let us reveal that substantial rearrangements of LHCII organization took place throughout the course of senescence com ­ prising a step-wise decline in relative abundance of subcom plexes 1 -3 (down to 0-58% of the initial abundance during 8 days of aging) and an increase in the relative abundance of the subcom plexes 4 and 5. Using SDS-PAGE and immunoblot analysis it was shown that the rearrangements were linked to the changes in the relative levels of LHCII apoproteins i.e. 26.7 and 25.6 kDa ones. The changes comprised the preferential disappearance of the 26.7 kDa polypeptide and an enrichment of 25.6 kD a one and most probably reflect the hetero­ geneity among LHCII apoproteins concerning their stability under the conditions of chi loss. Kinetin was able to repress the senescence-related rearrangements in LHCII subcomplex organization at late stages of aging (5 -8 days) by preventing over this time period the disap­ pearance of 26.7 kD a polypeptide and the enrichement of 25.6 kDa one. 
  Reference    Z. Naturforsch. 51c, 464 (1996); received Novem ber 23 1995/ 
  Published    1996 
  Keywords    Aging, Barley, Isoelectric Focusing, Polypeptide, Rearrangement 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0464.pdf 
 Identifier    ZNC-1996-51c-0464 
 Volume    51 
4Author    Sunkar Ramanjulu3, Werner Kaiser3, Karl-Josef Dietz3-Requires cookie*
 Title    Salt and Drought Stress Differentially Affect the Accumulation of Extracellular Proteins in Barley  
 Abstract    Barley (Hordeum vulgare) was grown for eight days in the presence of a range of salt concentrations or subjected to repeated cycles of wilting and rehydration. Changes in apoplastic protein content, protein pattern, enzymic activities and ion composition were in­ vestigated under salinity and drought. The protein content of intercellular washing fluid (IW F) increased 2.5-to 3.0-fold when the NaCl concentration in the growth medium was increased from 0 to 100 mM. The elevated protein content was the result of a general increase in most polypeptides and a pronounced increase in the abundance of specific polypeptides of apparent molecular masses of 15, 21, 22, 26, 36, 40 and 62 kDa. Conversely, the IW F protein content decreased during wilting similar as after application of colchicin, cytochalasin B or cycloheximide suggesting that inihibition of protein synthesis or vesicle transport may be the cause for the decrease in apoplastic protein content and enzyme activities in dehydrat­ ing plant tissue. The changes in apoplastic protein content were accompanied by stress-spe-cific alterations in activities of apoplastic enzymes. The greater apoplastic protein content was the consequence of stimulated protein synthesis in the presence of NaCl, as evidenced by increased incorporation of [35S]-methionine into IW F protein. The results demonstrate that the leaf apoplast is a compartment which sensitively and differentially responds to drought and salinity with consequences for plant growth. 
  Reference    Z. Naturforsch. 54c, 337—347 (1999); received February 5/February 23 1999 
  Published    1999 
  Keywords    Apoplast, Barley, Drought, Hydrolytic Enzymes, Polypeptide, Salinity 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0337.pdf 
 Identifier    ZNC-1999-54c-0337 
 Volume    54 
5Author    G. Rzegorz, Jackow Ski, EwA. KluckRequires cookie*
 Title    The Oligomeric Arrangement of the Light-Harvesting Chlorophyll a/6-Protein Complex of Photosystem II  
 Abstract    The light-harvesting chlorophyll a/b-protein complex of photosystem II (LHC II) was iso­ lated from carnation (Dianthus caryophyllus L.) leaves by K+-induced aggregation of «-hep-tylthioglucoside-treated photosystem II particles. When solubilized with a mixture of lithium docedyl sulphate, octyl-ß-D-glucopyranoside and dodecyl-ß-D-maltoside the LHC II was re­ solved by mild sodium dodecyl sulphate-polyacrylamide gel electrophoresis into four oligo­ meric forms and a monomeric one. LHC II contained five major polypeptides only two of which (27 and 26 kDa) were found to be its authentic components. The oligomeric forms of LHC II were found to differ in the stoichiometric ratios of the polypeptides present. The 26 kD a polypeptide was enriched in the largest oligomeric forms while the 27 kDa polypep­ tide tended to form a m onomer or to assemble as lower oligomeric states of LHC II. 
  Reference    Z. Naturforsch. 49c, 337—342 (1994); received October 26 1993/March 4 
  Published    1994 
  Keywords    1994 Carnation, Light-Harvesting Chlorophyll a/b-Protein Complex, Oligomer, Polypeptide, Stoichiometric Ratio 
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 TEI-XML for    default:Reihe_C/49/ZNC-1994-49c-0337.pdf 
 Identifier    ZNC-1994-49c-0337 
 Volume    49