Hemolithin: A Meteoritic Protein Containing Iron And Lithium

Model of the 2320 hemolithin molecule after MMFF energy minimization. Top: in space-filling mode; Center: ball and stick; Bottom: enlarged view of iron, oxygen and lithium termination. White = H; orange = Li; grey = C; blue = N; red = O and green = Fe. Hydrogen bonds are shown by dotted lines.

This paper characterizes the first protein to be discovered in a meteorite. Amino acid polymers previously observed in Acfer 086 and Allende meteorites [1,2] have been further characterized in Acfer 086 via high precision MALDI mass spectrometry to reveal a principal unified structure of molecular weight 2320 Daltons that involves chains of glycine and hydroxy-glycine residues terminated by iron atoms, with additional oxygen and lithium atoms.

Signal-to-noise ratios up to 135 have allowed the quantification of iron and lithium in the various MALDI fragments via the isotope satellites due to their respective minority isotopic masses 54Fe and 6Li. Analysis of the complete spectrum of isotopes associated with each molecular fragment shows 2H enhancements above terrestrial averaging 25,700 parts per thousand (sigma = 3,500, n=15), confirming extra-terrestrial origin and hence the existence of this molecule within the asteroid parent body of the CV3 meteorite class. The molecule is tipped by an iron-oxygen-iron grouping that in other terrestrial contexts has been proposed to be capable of absorbing photons and splitting water into hydroxyl and hydrogen moieties.

Malcolm. W. McGeoch, Sergei Dikler, Julie E. M. McGeoch
(Submitted on 22 Feb 2020)
Comments: 33 pages including 14 figures, 10 tables
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Chemical Physics (physics.chem-ph)
Cite as: arXiv:2002.11688 [astro-ph.EP] (or arXiv:2002.11688v1 [astro-ph.EP] for this version)
Submission history
From: Julie McGeoch
[v1] Sat, 22 Feb 2020 00:00:59 UTC (2,118 KB)
https://arxiv.org/abs/2002.11688
Astrobiology, Astrochemistry, Genomics

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