Hemolithin: a Meteoritic Protein containing Iron and Lithium

Title	Hemolithin: a Meteoritic Protein containing Iron and Lithium
Authors	Malcolm. W. McGeoch, Sergei Dikler, Julie E. M. McGeoch
Date	02/21/2020
Introduction	This paper presents the characterisation of the first protein identified within a meteorite. Building upon prior observations of amino acid polymers in Acfer 086 and Allende meteorites [1,2], this work provides a more detailed characterisation in Acfer 086 using high-precision MALDI mass spectrometry. The analysis unveils a primary unified structure with a molecular weight of 2320 Daltons, comprising chains of glycine and hydroxy-glycine residues. These chains are terminated by iron atoms, with additional oxygen and lithium atoms integrated into the structure. High signal-to-noise ratios, reaching up to 135, enabled the precise quantification of iron and lithium within various MALDI fragments through their isotopic satellites (specifically 54Fe and 6Li). Further isotopic analysis of each molecular fragment demonstrated 2H enhancements significantly above terrestrial levels, averaging 25,700 parts per thousand (with a sigma of 3,500 over 15 measurements). This isotopic signature strongly supports an extraterrestrial origin, affirming the presence of this molecule within the asteroid parent body of the CV3 meteorite class. Notably, the molecule features an iron-oxygen-iron grouping at one end, a configuration known in other terrestrial systems for its capacity to absorb photons and facilitate the cleavage of water into hydroxyl and hydrogen components.
Quote	Malcolm. W. McGeoch, Sergei Dikler and Julie E. M. McGeoch. Hemolithin: a Meteoritic Protein containing Iron and Lithium. 2020.
Element	Lithium (Li) , Oxygen (O) , Hydrogen (H) , Carbon (C)
Industry	Research & Laboratory , Space