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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
1
|
| pubmed:dateCreated |
1976-4-29
|
| pubmed:abstractText |
Statistical mechanical averages of vectors and tensors characterizing the configurations of polypeptides have been calculated for poly-L-alanines (PLA) of xu = 2-400 peptide units. These quantities are expressed in the reference frame of the first peptide unit, the X axis being situated along the virtual bond, the Y axis in the plane of the peptide unit. The persistence vector a identical to (r) converges rapidly with chain length to its limit a infinity which lies virtually in the XZ plane. Configurational averages of Cartesian tensors up to the sixth rank formed from the displacement vector p = r-a have been computed. For xu greater than 50 the even moments of fourth and sixth rank formed from the reduced vector p for the real chain are well repreented by the freely jointed chain with 21.7 virtual bonds equivalent to one of the model. The moments of p display assymmetry for xu less than 50. Density distribution functions Wa(p), evaluated from the three-dimensional Hermite series truncated at the term in the polynomial involving the tensors of p of sixth rank, display no obvious symmetry for xu less than 50. Approximate spherical symmetry of the distribution of p about a is observed only for xu greater than or equal to 100.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:issn |
0024-9297
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
9
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
41-7
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading | |
| pubmed:articleTitle |
Moments and distribution functions for polypeptide chains. Poly-L-alanine.
|
| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, Non-P.H.S.
|