ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The virgin (reactive-site Leu18-Glu19 peptide bond intact) and modified (reactive-site Leu18-Glu19 peptide bond hydrolyzed) forms of turkey ovomucoid third domain (OMTKY3 and OMTKY3*, respectively) have been analyzed by proton-detected 1H{13C} two-dimensional single-bond correlation (1H{13C}SBC) spectroscopy. Previous 1H-nmr assignments of these proteins [A. D. Robertson, W. M. Westler, and J. L. Markley (1988) Biochemistry, 27, 2519-2529; G. I. Rhyu and J. L. Markley (1988) Biochemistry, 27, 2529-2539] have been extended to directly bonded 13C atoms. Assignments have been made to 52 of the 56 backbone 13Cα-1H units and numerous side-chain 13C-1H groups in both OMTKY3 and OMTKY3*. The largest changes in the 13C chemical shift upon conversion of OMTKY3 to OMTKY3* occur at or near the reactive site, and tend toward values observed in small peptides. Moreover, the side-chain prochiral methylene protons attached to the Cγ of Glu19 and Cδ of Arg21 show nonequivalent chemical shifts in OMTKY3 but more equivalent chemical shift in OMTKY3*. These results suggest that the reactive site region becomes less ordered upon hydrolysis of the Leu18-Glu19 peptide bond. Comparison of 13Cα chemical shifts of OMTKY3 and bovine pancreatic trypsin inhibitor [D. Brühuiler and G. Wagner (1986) Biochemistry 25, 5839-5843; N. R. Nirmala and G. Wagner (1988) Journal of the American Chemical Society, 110, 7557-7558] with small peptide values [R. Richarz and K. Wüthrich (1978) Biopolymers, 17, 2133-2141] suggests that 13Cα chemical shifts of residues residing in helices are generally about 2 ppm downfield of resonances from nonhelical residues.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360290216
