electrons in β-radiation produced by radioactive decay were chiral, in the sense that they could exist in two spin states that were mirror images. Interestingly, these electrons highly favored a left-handed spin state. Vester and Ulbricht investigated the interaction of this polarized radiation with chemical molecules to see if the radiation could induce chirality. Although they observed only a small effect, the Vester-Ulbricht hypothesis gained in popularity as an explanation for why nature favored one type of enantiomer when it came to biological molecules like sugars, amino acids—and DNA.
Over fifty years later, researchers at the University of Nebraska provided evidence that supported the Vester-Ulbricht hypothesis (3). They studied the chiral molecule bromocamphor and observed that polarized β-radiation preferentially dissociated one enantiomer of bromocamphor in the gas phase. That is, left-handed electrons preferentially destroyed left-handed bromocamphor enantiomers. Once again, the magnitude of this “chiral bias” effect was small, but it suggested the intriguing possibility that, in the distant past, polarized cosmic radiation could have selectively destroyed the precursors of left-handed DNA.
https://www.promegaconnections.com/left-handed-dna-is-that-right/
https://www.youtube.com/watch?v=_wDIe0XEmwI
depends what level or type of molecule. Cosmic radiation electrons are left-handed spin, thus destroying left-handed amino acids. We digest right-handed sugar but we have left-handed amino acids but right-handed twist to DNA as one chromatid. "the DNA double helix itself is primarily a right-handed structure, the higher-order organization of chromatin within chromatids, known as the chromonema, appears to be a helically coiled structure with a less fixed handedness, and the direction can vary"
No comments:
Post a Comment