Nuclear overhauser enhancement demonstration of the type II β-turn in repeat peptides of tropoelastin

1976 ◽  
Vol 70 (2) ◽  
pp. 485-491 ◽  
Author(s):  
Md.Abu Khaled ◽  
Dan W. Urry
Keyword(s):  
Type Ii ◽  
Nuclear Overhauser Enhancement ◽  
Nuclear Overhauser

scholarly journals Solution structures of nisin A and its two major degradation products determined by n.m.r

1992 ◽  
Vol 283 (2) ◽  
pp. 413-420 ◽  
Author(s):  
L Y Lian ◽  
W C Chan ◽  
S D Morley ◽  
G C Roberts ◽  
B W Bycroft ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Ring Opening ◽  
Polypeptide Chain ◽  
Degradation Products ◽  
Correlation Spectroscopy ◽  
Solution Structures ◽  
Stimulated Annealing ◽  
Nuclear Overhauser Enhancement ◽  
Stereospecific Assignments ◽  
Nuclear Overhauser

The conformations of nisin and two major degradation products, nisin-(1-32)-peptide (nisin1-32) and des-delta Ala5-nisin1-32 (where delta Ala is alpha beta-didehydroalanine), in aqueous solution have been determined from n.m.r. data. Sequential assignments of the peptides using correlation spectroscopy (‘COSY‘), homonuclear Hartmann-Hahn spectroscopy (‘HOHAHA’), nuclear Overhauser enhancement spectroscopy (NOESY), relayed NOESY and rotating-frame nuclear Overhauser spectroscopy (ROESY) experiments are presented, including stereospecific assignments of beta-methylene protons of the lanthionine residues. ROESY experiments are also used to detect flexible regions in the polypeptide chain. A dynamic-stimulated-annealing approach is used for structural determination. It can be concluded that all these peptides are flexible in aqueous solution, with no experimental evidence of preferred overall conformations; the only defined conformational features are imposed by the presence of the lanthionine residues. Low-temperature studies also reveal that des-delta Ala5-nisin1-32 adopts conformations similar to those when the ring is intact, suggesting that the loss of activity of this degradation product is due to the absence of the delta Ala5 residue rather than to the conformational consequences of ring-opening.

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