Homochirality is a uniformity of chirality, or handedness. Objects are chiral when they cannot be superposed on their mirror images. For example, the left and right hands of a human are approximately mirror images of each other but are not their own mirror images, so they are chiral. In biology, 19 of the 20 natural amino acids are homochiral, being L-chiral (left-handed), while sugars are D-chiral (right-handed).[1] Homochirality can also refer to enantiopure substances in which all the constituents are the same enantiomer (a right-handed or left-handed version of an atom or molecule), but some sources discourage this use of the term.
It is unclear whether homochirality has a purpose; however, it appears to be a form of information storage.[2] One suggestion is that it reduces entropy barriers in the formation of large organized molecules.[3] It has been experimentally verified that amino acids form large aggregates in larger abundance from an enantiopure samples of the amino acid than from racemic (enantiomerically mixed) ones.[3]
It is not clear whether homochirality emerged before or after life, and many mechanisms for its origin have been proposed.[4] Some of these models propose three distinct steps: mirror-symmetry breaking creates a minute enantiomeric imbalance, chiral amplification builds on this imbalance, and chiral transmission is the transfer of chirality from one set of molecules to another.
^Nelson, Lehninger; et al. (2008). Lehninger Principles of Biochemistry. Macmillan. p. 474.
^Carroll, James D. (March 2009). "A new definition of life". Chirality. 21 (3): 354–358. doi:10.1002/chir.20590. PMID 18571800.
^ abJulian, Ryan R.; Myung, Sunnie; Clemmer, David E. (January 2005). "Do Homochiral Aggregates Have an Entropic Advantage?". The Journal of Physical Chemistry B. 109 (1): 440–444. doi:10.1021/jp046478x. PMID 16851034. S2CID 10599051.
^Cite error: The named reference jafarpour2017 was invoked but never defined (see the help page).
is the origin of homochirality in living organisms? (more unsolved problems in chemistry) Theories for the origin of homochirality in the molecules of...
Her thesis was Theoretical Models for the Emergence of Biomolecular Homochirality and her doctoral advisor was Marcelo Gleiser. After graduating from...
reaction. She was the first to conclude that a homochiral dimer was the active catalyst in promoting homochirality for the Soai reaction. More recently, Blackmond...
around the world. In 2012, his paper "Evidence for the Likely Origin of Homochirality in Amino Acids, Sugars, and Nucleosides on Prebiotic Earth" was retracted...
right-handed sugars. This phenomenon is known as homochirality. It is not known whether homochirality emerged before or after life, whether the building...
vents as well as hot springs with raw material for further development. Homochirality is the geometric uniformity of materials composed of chiral (non-mirror-symmetric)...
prevalence of homochirality in living organisms is currently unknown and is often connected to the origin of life itself. Whether homochirality emerged before...
excess. The reaction has been studied for clues about the origin of homochirality among certain classes of biomolecules. The Japanese chemist Kensō Soai...
equal amount of each. Somehow life must have developed this preference (homochirality); but while scientists have proposed several theories, they have no...
2011). "A model of proto-anti-codon RNA enzymes requiring L-amino acid homochirality". Journal of Molecular Evolution. 73 (1–2): 10–22. Bibcode:2011JMolE...
Extraterrestrial life Extraterrestrial liquid water Forbidden mechanism Homochirality Intergalactic dust Interplanetary medium Interstellar medium Photodissociation...
right-handed. A team of chemists in Sweden demonstrated in 2005 that this homochirality could have been triggered or catalyzed by the action of a left-handed...
Extraterrestrial life Extraterrestrial liquid water Forbidden mechanism Homochirality Intergalactic dust Interplanetary medium Interstellar medium Photodissociation...
p. 2. Blackmond, Donna G. (2016-11-20). "The Origin of Biological Homochirality". Cold Spring Harbor Perspectives in Biology. 2 (5): a002147. doi:10...
Extraterrestrial life Extraterrestrial liquid water Forbidden mechanism Homochirality Intergalactic dust Interplanetary medium Interstellar medium Photodissociation...
meteoritic organic compounds in elucidating the evolution of planetary homochirality. Pizzarello was a project collaborator and co-investigator for the NASA...
Retrieved 2022-08-09. Blackmond, D. G. (2019). "The Origin of Biological Homochirality". Cold Spring Harbor Perspectives in Biology. 11 (3): a032540. doi:10...
conditions. This fact also leads to the question of how biological homochirality evolved on what is presumed to be a racemic primordial earth. The reagents...
Extraterrestrial life Extraterrestrial liquid water Forbidden mechanism Homochirality Intergalactic dust Interplanetary medium Interstellar medium Photodissociation...
Extraterrestrial life Extraterrestrial liquid water Forbidden mechanism Homochirality Intergalactic dust Interplanetary medium Interstellar medium Photodissociation...
Extraterrestrial life Extraterrestrial liquid water Forbidden mechanism Homochirality Intergalactic dust Interplanetary medium Interstellar medium Photodissociation...
Donna G. (2020). "Autocatalytic Models for the Origin of Biological Homochirality". Chemical Reviews. 120 (11): 4831–4847. arXiv:1909.13015. doi:10.1021/acs...
Extraterrestrial life Extraterrestrial liquid water Forbidden mechanism Homochirality Intergalactic dust Interplanetary medium Interstellar medium Photodissociation...
Extraterrestrial life Extraterrestrial liquid water Forbidden mechanism Homochirality Intergalactic dust Interplanetary medium Interstellar medium Photodissociation...
Extraterrestrial life Extraterrestrial liquid water Forbidden mechanism Homochirality Intergalactic dust Interplanetary medium Interstellar medium Photodissociation...
Extraterrestrial life Extraterrestrial liquid water Forbidden mechanism Homochirality Intergalactic dust Interplanetary medium Interstellar medium Photodissociation...
Extraterrestrial life Extraterrestrial liquid water Forbidden mechanism Homochirality Intergalactic dust Interplanetary medium Interstellar medium Photodissociation...
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