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Nuclear magnetic resonance and optical spectroscopic studies of block copolymers of polypeptides. I. Block copoly[(benzyl‐ L ‐glulamate) n : (benzyl‐ L ‐aspartate) m ]
Author(s) -
Paolillo L.,
Temussi P.,
Trivellone E.,
Bradbury E. M.,
CraneRobinson C.
Publication year - 1971
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360101215
Subject(s) - copolymer , chemistry , block (permutation group theory) , random coil , sense (electronics) , stereochemistry , helix (gastropod) , nuclear magnetic resonance spectroscopy , chemical shift , crystallography , circular dichroism , polymer , organic chemistry , combinatorics , ecology , mathematics , snail , biology
In a study of A–B type block copolymers of γ benzyl‐ L ‐gultamate and β‐benzyl‐ L ‐aspartate use has been made of the observations: ( 1 ) that for poly aspartate esters the chemical shifts of the α‐C H and N H resonances are sensitive to the helix sense, ( 2 ) that in both helical and random coil conformations the same resonances of poly‐γ‐benzyl‐ L ‐glutamate are well separated from those of poly aspartates. Since the sense of poly‐β‐benzyl‐ L ‐aspartate is very sensitive to the inclusion of γ‐benzyl‐ L ‐glutamate residues, the degree of overlap between the blocks can be studied by monitoring the helix sense of the aspartate. The ability of the NMR method to make separate observation of the two blocks removes the necessity of relying on an overall ORD parameter such as b 0 . The copolymers studied include those having lefthanded, righthanded, and mixed‐sense aspartate, corresponding to differing degrees of overlap.