ISSN:
1573-0689
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Physics
Notes:
Abstract The application of optical second harmonic generation (SHG) to the study of non-centrosymmetry in 71α-amino acids, 22 dipeptides, 6 tripeptides, 16 proteins, and 5 viruses is reported. Allα-amino acids exceptα-glycine, all peptides containing at least one enantiomericα-amino acid residue, and all proteins and viruses are found to be non-centrosymmetric. Of the 22 racemicα-amino acids investigated, 19 form centrosymmetric crystalline racemates. DL-alanine and DL-norleucine form non-centrosymmetric racemates whereas DL-glutamic acid does not form racemic crystals except when hydrated. These results lead us to suggest that non-centrosymmetry and its consequences (i.e., allowable piezoelectricity and possible pyroelectricity) is an essential and universal property of all biological systems. Furthermore, the concept of polarization homeostasis (i.e., biomolecules in vivo have a macroscopic equilibrium polarization in which the polarization ≠0) is proposed as a basic biological phenomenon and shown to be consistent with the dominance of one enantiomeric configuration ofα-amino acids in nature, natural selection and mutationally induced molecular diseases.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02328933
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