Carbon-13 relaxation behavior in multiply enriched systems: (90%-1,2-/sup 13/C/sub 2/-Gly/sup 6/)Bradykinin
- Los Alamos National Lab., NM
The relaxation behavior of macromolecules multiply enriched in /sup 13/C has been investigated theoretically, and results for (90%-1,2-/sup 13/C/sub 2/-Gly/sup 6/) bradykinin have been interpreted on the basis of this theory. The /sup 13/C-/sup 13/C dipolar interaction can be selectively observed by comparing the relaxation behavior of the singly labeled (center) and doubly labeled satellite /sup 13/C resonances, and the results can be used to evaluate the rotational correlation time of carbon-carbon bonds. In both the present study and all of the multiple labeling studies reported to date, the rotational correlation times thus obtained (tau/sub CC/) are significantly longer than the rotational correlation times (tau/sub CH/) obtained in the usual way on the basis of relaxation analysis of protonated carbons. The spin-lattice relaxation behavior for doubly /sup 13/C labeled system falls into three limits: (1) extreme narrowing limit in which the /sup 13/C-/sup 1/H and /sup 13/C-/sup 13/C dipolar interactions are additive; (2) spin-diffusion limit in which the relaxation rate is limited by the rate of /sup 13/C-/sup 13/C flip-flop interactions leading to spin diffusion; (3) spin-diffusion limit in which the rate is determined by the protonated carbon which becomes a relaxation sink. In addition to the spin-lattice relaxation differences between singly and multiply labeled molecules, significant line-width differences are also observed.
- OSTI ID:
- 5177599
- Journal Information:
- Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 21; ISSN BICHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
BIOCHEMISTRY
BRADYKININ
CARBON 13
CARBON ISOTOPES
CHEMISTRY
CONFIGURATION INTERACTION
CONFORMATIONAL CHANGES
EVEN-ODD NUCLEI
ISOTOPES
KININS
LABELLED COMPOUNDS
LIGHT NUCLEI
MAGNETIC RESONANCE
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
NUCLEI
ORGANIC COMPOUNDS
PEPTIDES
POLYPEPTIDES
PROTEINS
RELAXATION
RESONANCE
SOLUBILITY
SPIN-LATTICE RELAXATION
STABLE ISOTOPES
STRUCTURAL CHEMICAL ANALYSIS