Chemistry of Life Changes-NASA Scientists Put Arsenic On Life Backbone

in environment, biology

Arsenic was not known to be important in the formation of life, it was always considered as a poison.  Now NASA scientists say life can very well sustain if arsenic replaces phosphorous in the basic builiding blocks of life, DNA and RNA.

Researchers conducting tests in the harsh environment of Mono Lake in California have discovered the first known microorganism on Earth able to thrive and reproduce using the toxic chemical arsenic. The microorganism substitutes arsenic for phosphorus in its cell components.

"The definition of life has just expanded," said Ed Weiler, NASA's associate administrator for the Science Mission Directorate at the agency's Headquarters in Washington. "As we pursue our efforts to seek signs of life in the solar system, we have to think more broadly, more diversely and consider life as we do not know it."

Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur are the six basic building blocks of all known forms of life on Earth. Phosphorus is part of the chemical backbone of DNA and RNA, the structures that carry genetic instructions for life, and is considered an essential element for all living cells.

Phosphorus is a central component of the energy-carrying molecule in all cells (adenosine triphosphate) and also the phospholipids that form all cell membranes. Arsenic, which is chemically similar to phosphorus, is poisonous for most life on Earth. Arsenic disrupts metabolic pathways because chemically it behaves similarly to phosphate.

The research was published in the recent issue of Science Express, a publication of Science Magazine.



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Will there be increased mutation

It is interesting. Need to find how stable this bond is and what is the rate of mutation when arsenic substitutes phosphorous