The full text of this article hosted at iucr.org is unavailable due to technical difficulties.

Regular Article

Ortho–para spin isomers of the protons in the methylene group—Possible implications for protein structure*

Meir Shinitzky

Corresponding Author

E-mail address:meir.shinitzky@weizmann.ac.il

Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel

Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
Search for more papers by this author
Avshalom C. Elitzur

Rector's Office, Bar‐Ilan University, Ramat‐Gan, Israel

Search for more papers by this author
First published: 19 July 2006
Cited by: 10
*

Dedicated to Prof. Ephraim Katchalski on his 90th birthday.

Abstract

The two hydrogen atoms attached to the carbon in the methylene group are of two different spin configurations, similar to those in the case of water: ortho, where the two proton spins are parallel to each other, and para, where they are antiparallel. The ortho configuration has three degenerate states, while the para configuration is singular, leading to a statistical ratio of these isomers 3:1 ortho/para. Such spin isomers are present in glycine and most chiral amino acids where they may induce broadening of structural zones, a possibility which remains to be assessed. The implications of this neglected possibility could be far‐reaching, in particular with respect to protein structure and the origins of biochirality. Chirality, 2006 © 2006 Wiley‐Liss, Inc.

Number of times cited: 10

  • , Determining Amino Acid Chirality in the Supernova Neutrino Processing Model, Handbook of Supernovae, 10.1007/978-3-319-21846-5_20, (2383-2399), (2017).
  • , Selection of Amino Acid Chirality via Neutrino Interactions with 14N in Crossed Electric and Magnetic Fields, Astrobiology, (2017).
  • , Determining Amino Acid Chirality in the Supernova Neutrino Processing Model, Handbook of Supernovae, 10.1007/978-3-319-20794-0_20-1, (1-17), (2016).
  • , Determining Amino Acid Chirality in the Supernova Neutrino Processing Model, Symmetry, 6, 4, (909), (2014).
  • , References, Hydrogen Energy for Beginners, 10.1201/b15456-13, (267-316), (2013).
  • , Intermolecular chiral assemblies in R(−) and S(+) 2‐butanol detected by microcalorimetry measurements, Chirality, 24, 7, (500-505), (2012).
  • , Supernovae, Neutrinos and the Chirality of Amino Acids, International Journal of Molecular Sciences, 12, 12, (3432), (2011).
  • , Enantiodifferent Proton Exchange in Alanine and Asparagine in the Presence of H 2 17 O, Journal of Molecular Evolution, 71, 1, (23), (2010).
  • , Mirror symmetry breaking of silicon polymers—from weak bosons to artificial helix, The Chemical Record, 9, 5, (271-298), (2009).
  • , Molecular homochirality and the parity‐violating energy difference. A critique with new proposals, Chirality, 20, 2, (84-95), (2007).