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Hemolithin

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Hemolithin
(iron and lithium-containing protein,
possibly extraterrestrial[1][2][3][4][5][6][7][8])
Allende meteorite slice ASU.jpg
Hemolithin was found in Acfer 086,[9][10] an Allende meteorite similar to that pictured.
Protein type{{{protein_type}}}
Functionunknown, although possibly able to split water to hydroxyl and hydrogen molecules[1]
Subunit name Gene Chromosomal locus
{{{subunit1}}} {{{gene1}}} {{{locus1}}}
{{{subunit2}}} {{{gene2}}} {{{locus2}}}

Hemolithin is an iron and lithium-containing protein, purported to be found inside a meteorite called Acfer 086,[9] a CV3 carbonaceous chondrite Allende meteorite, and thought to be the first protein discovered that may be of extraterrestrial origin.[1][2][3][4][5][6][7][8] The protein was detected by teams of scientists, led by biochemist Julie McGeoch, from Harvard University, and from the biotech and physics companies of Bruker Scientific and the superconductor X-ray source supplier PLEX Corporation.[1][3][4][5][6][7][8] The study is an extension of published and unpublished results by the teams.[11][12][13]

Source[edit]

The detected hemolithin protein was reported to have been found inside a meteorite called Acfer 086,[9] a CV3 carbonaceous chondrite Allende meteorite, which was discovered in Agemour, Algeria in 1990.[3][6][10]

Structure[edit]

Hemolithin, the newly found protein, was found, aided by the use of "state-of-the-art" mass spectrometry, to be largely composed of glycine, hydroxyglycine and amino acids.[14] Hemolithin also contained atoms of oxygen, lithium and iron in an up-to-now unobserved arrangement.[8] The researchers noted that the protein was related to “very high extraterrestrial" ratios of Deuterium/Hydrogen (D/H);[3] such high D/H ratios are not found anywhere on Earth, but are "consistent with long-period comets"[6] and suggest, as reported, "that the protein was formed in the proto-solar disc or perhaps even earlier, in interstellar molecular clouds that existed long before the Sun’s birth".[3]

A natural development of hemolithin may have started with glycine forming first, and then later linking with other glycine molecules into polymer chains, and later still, combining with iron and oxygen atoms. The iron and oxygen atoms reside at the end of the newly found molecule. The researchers speculate that the iron oxide grouping formed at the end of the molecule may be able to absorb photons, thereby enabling the molecule to split water (H2O) into hydrogen and oxygen and, as a result, produce a source of energy that might be useful to the development of life.[3]

Nonetheless, exobiologist and chemist Jeffrey Bada expressed concerns about the possible protein discovery commenting, "The main problem is the occurrence of hydroxyglycine, which, to my knowledge, has never before been reported in meteorites or in prebiotic experiments. Nor is it found in any proteins. ... Thus, this amino acid is a strange one to find in a meteorite, and I am highly suspicious of the results."[14] Although some scientists seem supportive of the study, other scientists may be less so.[15] [Note: Research Author Reply]:[16] "On the question of hydroxy glycine in hemolithin, there is presented in the Hemolithin MS[2] very clear evidence of multiple oxidations of a 17 glycine polymer: The hemolithin MS (arXiv)[2] shows in figure S3.3 a characteristic oxidation series in which 2, 3, 4, 5, and 6 oxygen atoms bond to glycine residues within a 17 glycine chain. This converts the corresponding numbers of mass 57 glycine residues into mass 73 hydroxy glycine residues (MS pages 27 and 28).[2]"

Significance[edit]

The possible finding of the hemolithin protein supports the notion that life on Earth may not have started on Earth after all, but may have come from outer space instead – a process known as panspermia.[8]

Besides this possible discovery of an extraterrestrial protein, other evidences of complex chemistry (amino acids, polycyclic aromatic hydrocarbons, sugars, ribose, tholins) occurring in outer space have been accumulating from recent astrobiology studies, including those related to meteorites and comets. The presence of such complex chemistry occurring in the cosmos, as well as the observation by biologist Stephen Blair Hedges that life may have arisen quickly on the very early Earth,[17][18][19] suggests that life may be widespread thoughout the universe.[14]

See also[edit]

References[edit]

  1. 1.0 1.1 1.2 1.3 McGeoch, Malcolm. W.; Dikler, Sergei; McGeoch, Julie E. M. (22 February 2020). "Hemolithin: a Meteoritic Protein containing Iron and Lithium". arXiv:2002.11688 [astro-ph.EP].
  2. 2.0 2.1 2.2 2.3 2.4 McGeoch, Malcolm. W.; Dikler, Sergei; McGeoch, Julie E. M. (22 February 2020). "Hemolithin: a Meteoritic Protein containing Iron and Lithium - PDF". arXiv:2002.11688 [astro-ph.EP].
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Ferreira, Becky (28 February 2020). "A Key Ingredient for Life Has Been Found on an 'Extraterrestrial Source,' Scientists Report in this unpublished report". Vice. Retrieved 2 March 2020.
  4. 4.0 4.1 4.2 McGeoch, Julie (29 February 2020). "Hemolithin: A Meteoritic Protein Containing Iron And Lithium". Astrobiology.com. Retrieved 2 March 2020.
  5. 5.0 5.1 5.2 Irving, Michael (1 March 2020). "Extraterrestrial protein discovered in meteorite for the first time". NewAtlas.com. Retrieved 2 March 2020.
  6. 6.0 6.1 6.2 6.3 6.4 Starr, Michelle (2 March 2020). "Scientists Claim to Have Found The First Known Extraterrestrial Protein in a Meteorite". ScienceAlert.com. Retrieved 2 March 2020.
  7. 7.0 7.1 7.2 Young, Chris (2 March 2020). "Scientists Find the First Extraterrestrial Protein in a Meteorite - The new discovery could provide clues as to whether extraterrestrial life is possible". InterestingEngineering.com. Retrieved 2 March 2020.
  8. 8.0 8.1 8.2 8.3 8.4 Yirka, Bob (3 March 2020). "Protein discovered inside a meteorite". Phys.org. Retrieved 3 March 2020.
  9. 9.0 9.1 9.2 Staff (3 March 2020). "Acfer 086". The Meteoritical Society. Retrieved 3 March 2020.
  10. 10.0 10.1 Wlotza, Frank (1 September 1991). "Meteoritical Bulletin, No. 71". Meteoritical Bulletin. 26 (71): 255–262. Bibcode:1991Metic..26..255W. doi:10.1111/j.1945-5100.1991.tb01047.x. Retrieved 7 March 2020.
  11. McGeoch, J.E.M.; McGeoch, M.W. (2015). "Polymer amide in the Allende and Murchison meteorites". Meteoritics & Planetary Science. 50 (12): 1971–1983. Bibcode:2015M&PS...50.1971M. doi:10.1111/maps.12558.
  12. McGeoch, Julie E. M.; McGeoch, Malcolm. W (28 July 2017). "A 4641Da polymer of amino acids in Acfer-086 and Allende meteorites". arXiv:1707.09080 [astro-ph.EP].
  13. McGeoch, Malcolm. W.; Samoril, Tomas; Zapotok, David; McGeoch, Julie E. M. (28 July 2017). "Polymer amide as a carrier of 15N in Allende and Acfer 086 meteorites". arXiv:1811.06578 [astro-ph.EP].
  14. 14.0 14.1 14.2 Wall, Mike (3 March 2020). "First known extraterrestrial protein possibly spotted in meteorite". Space.com. Retrieved 3 March 2020.
  15. Crane, Leah (3 March 2020). "Have we really found an alien protein inside a meteorite?". New Scientist. Retrieved 3 March 2020.
  16. Mcgeoch (7 March 2020). "Wikipedia – User talk:Mcgeoch – Comments and Corrections". Wikipedia. Retrieved 7 March 2020.
  17. Borenstein, Seth (19 October 2015). "Hints of life on what was thought to be desolate early Earth". Associated Press. Retrieved 3 March 2020.
  18. Schouten, Lucy (20 October 2015). "When did life first emerge on Earth? Maybe a lot earlier than we thought". The Christian Science Monitor. Boston, Massachusetts: Christian Science Publishing Society. ISSN 0882-7729. Archived from the original on 22 March 2016. Retrieved 3 March 2020.
  19. Johnston, Ian (2 October 2017). "Life first emerged in 'warm little ponds' almost as old as the Earth itself - Charles Darwin's famous idea backed by new scientific study". The Independent. Retrieved 3 March 2020.

External links[edit]


Others articles of the Topics Astronomy AND Biology : The Joy of Science

Others articles of the Topic Astronomy : Robin Heath, Betelgeuse, Rigel, The Joy of Science, Orbit-Vis, Cosmic web, AT 2018pw

Others articles of the Topic Biology : Fossil Taxon, The Joy of Science


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