Switch to
| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
2
|
| pubmed:dateCreated |
1989-6-20
|
| pubmed:abstractText |
C hordein, a storage protein from barley grains, has an Mr of about 53,000, and consists predominantly of repeated octapeptides with a consensus sequence of Pro-Gln-Gln-Pro-Phe-Pro-Gln-Gln. Previously reported hydrodynamic and c.d. studies indicate the presence of beta-turns, the repetitive nature of which may lead to the formation of a loose spiral. In order to study these turns we have compared the structures of a synthetic peptide corresponding to the consensus repeat motif and total C hordein by using c.d. and Fourier-transform i.r. spectroscopy. The synthetic peptide exhibited spectra typical of beta I/III reverse turns when dissolved in trifluoroethanol at 22 degrees C and in water at 70 degrees C, but 'random-coil'-like spectra in water at 22 degrees C. The whole protein also showed increases in beta I/III reverse turns when dissolved in increasing concentrations of trifluoroethanol (50-100%, v/v) or heated in ethanol/water (7:3, v/v). Two cryogenic solvent systems were used to determine the c.d. spectra of the peptide and protein at temperatures down to -100 degrees C. Methanol/glycerol (9:1, v/v) and ethanediol/water (2:1, v/v) were selected as analogues of trifluoroethanol/water and water respectively. The peptide exhibited beta I/III-reverse-turn and 'random-coil'-like spectra in methanol/glycerol and ethanediol/water respectively at 22 degrees C, but a spectrum similar to that of a poly-L-proline II helix in both solvents at -100 degrees C. Similarly the proportion of this spectral type also increased when the whole protein was cooled in both solvents. These results indicate that a poly-L-proline II conformation at low temperatures is in equilibrium with a beta I/III-turn-rich conformation at higher temperatures. The latter conformation is also favoured in solvents of low dielectric constant such as trifluoroethanol. The 'random-coil'-like spectra exhibited by the protein and peptide in high-dielectric-constant solvents at room temperature may result from a mixture of the two conformations rather than from the random-coil state.
|
| pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-1156632,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-15915586,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-3232,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-3233285,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-3255313,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-3430626,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-354496,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-3768484,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-3773734,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-3773736,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-3994673,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-4351002,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-5016973,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-5685102,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-592361,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-6698719,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-7002463,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-7295645,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-7378550,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-7417259,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2719660-82446
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Apr
|
| pubmed:issn |
0264-6021
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
15
|
| pubmed:volume |
259
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
471-6
|
| pubmed:dateRevised |
2009-11-19
|
| pubmed:meshHeading | |
| pubmed:year |
1989
|
| pubmed:articleTitle |
Conformational studies of a synthetic peptide corresponding to the repeat motif of C hordein.
|
| pubmed:affiliation |
Department of Biochemistry, A.F.R.C. Institute of Arable Crops Research, Rothamsted Experimental Station, Harpenden, Herts, U.K.
|
| pubmed:publicationType |
Journal Article
|