ISSN:
0749-1581
Keywords:
13C NMR
;
Protein dynamics
;
Serine protease inhibitor
;
Protein engineering
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Carbon-13 T1 and NOE measurements were used to study the internal motions of the single phenylalanine residue in CI-2 and in a mutant in which an arginine residue adjacent to the Phe had been replaced with an alanine residue. Each protein was specifically enriched with [13C6-ring]phenylalanine. The arginine to alanine modification resulted in a reduction of the order parameter, S2, from 0.39 to 0.32 for the internal motions of the aromatic ring. This is consistent with the aromatic side-chain of Phe 69 being less restricted, as a consequence of the removal of the neighbouring bulky side chain. Wild-type CI-2 was also successfully enriched with [2-13C]glycine. An average order parameter of 0.60 was obtained for the α-carbon positions of the three glycine residues. When bound to the serine protease chymotrypsin, S2 remains unchanged within experimental error. However, the overall tumbling, derived from NMR, slows by a factor of 5, consistent with the increase in molecular weight.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260301215
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