Galactic distribution of chirality sources of organic molecules

Abstract

Conceptualizing planetary habitability depends on understanding how living organisms originated and what features of environments are essential to foster abiogenesis. Estimates of the abundance of life's building blocks are confounded by incomplete knowledge of the role of chirality and racemization in organic compounds in the origination of living organisms. Chirality is an essential feature of enzymes as well as many lock-and-key type structures. There are four known processes that can act on complex organic molecules to promote racemization for abiogenesis: quantum-tunneling effects; selection via interaction with circularly polarized light (CPL); templating processes; and interactions with electrical and magnetic (EM) fields. These occur in different places, respectively: cold interstellar space; regions of space with energetic photons, dust and/or magnetic fields; and mineral surfaces (for both templating and EM fields). Chirality as a feature of terrestrial life suggests neither a special place for local development of homochirality nor for extra-terrestrial enrichment and delivery. The presence of these molecules in three competing scenarios for life's origin-chemical gardens, geothermal fields, and ice substrates-relies on a framework of hypothesis and estimation. An easily-modified worksheet is included in the supplemental material that allows a user to generate different scenarios and data related to the distribution of chiral organic molecules as building blocks for living organisms within the galaxy. A simple hypothetical mechanism for planetary magnetic field reversals, based on a high-density plasma inner core, is also presented as a means to aid in estimating field polarity and hence the orientation of racemization processes based on planetary magnetic fields.

Preparation and Evaluation of a Cholesterol Derivatized β-Cyclodextrin-bonded Phase for Achiral and Chiral HPLC

“…Since the chirality of proteins, biological enzymes and antigen-antibodies, these macromolecules tend to exhibit highly enantioselectivity in terms of acting with chiral compounds. [1][2][3][4] In most cases, only one of the enantiomers has the desired efficacy, while the remaining enantiomers are often inactive and even toxic. A case in point is that the R-propranolol is 300 times less effective than the S-propranolol in the treatment of hypertension, and the worse is that the former will cause male infertility.…”