STRUCTURE AND ORIENTATION OF FREE RADICALS FORMED BY IONIZING RADIATIONS IN CERTAIN NATIVE PROTEINS

Journal Article · Mon Aug 01 04:00:00 EDT 1960 · Proc. Natl. Acad. Sci. U.S.

DOI:https://doi.org/10.1073/pnas.46.8.1124· OSTI ID:4156384

Gordy, W; Shields, H

Studies of the doublet pattern in the electron spin resonance of free radicals produced by irradiation of proteins indicated that it must arise from a proton on the CH group within the free radical. Analysis of the electron spin resonance of irradiated silk revealed a doublet of 26 gauss separation for silk strands parallel to the field and an incompletely resolved doublet of 13 gauss separation for the strands perpendicular to the field. These observed features were accounted for by the assumption of the free radical which would be formed by the loss of the R. group from a unit section of the polypeptide chain. An analysis of the electron spin resonance of an irradiated feather quill showed a superposition of the silk-like doublet and the cysteine-like resonance. From these studies it was determined that the two principle sites of radiation damage to proteins were the alpha -carbon in the polypeptide backbone and the sulfur atom of a side chain of the capture or cystine residue. Structural arrangement and the nature of coiling were found to influence the movement of electron vacancies within proteins. (M.C.G.)

• Research Organization: Duke Univ., Durham, N.C.
• Sponsoring Organization: USDOE
• NSA Number: NSA-14-022732
• OSTI ID: 4156384
• Journal Information: Proc. Natl. Acad. Sci. U.S., Journal Name: Proc. Natl. Acad. Sci. U.S. Vol. Vol: 46
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

BIOLOGY AND MEDICINE
FEATHERS
IRRADIATION
PROTEINS
SILK
SKIN