Sugars As the Source of Energized Carbon for Abiogenesis

Astrobiology Science Conference 2010 (2010) 5095.pdf

SUGARS AS THE SOURCE OF ENERGIZED CARBON FOR ABIOGENESIS. A. L. Weber, SETI Institute, NASA Ames Research Center, Mail Stop 239-4, Moffett Field, CA, 94035-1000, [email protected]

Abstract: As shown in Figure 1, abiogenesis has sev- eral requirements: (A) a source of organic substrates and chemical energy that drives the synthesis of (B) useful small molecules (ammonia, monomers, metabo- lites, energy molecules), and (C) a second synthetic processs that yields large replicating and catalytic polymers that control (D) the growth and maintenance of a primitive protocell. Furthermore, the required chemical energy must be sustained and effectively coupled to individual reactions to drive biosynthesis at a rate that counters chemical degradation. Energy coupling would have been especially difficult during the origin of life before the development of powerful enzyme catalysts with 3-D active sites. To solve this energy coupling problem we have investigated abiogenesis using sugar substrates whose energized carbon groups drive spontaneous synthetic self-transformation reactions that yield: biometabolites, catalytic molecules, energy-rich thioesters, amino acids, plausible alternative nucleobases and cell-like microstructures [1-8]. Recently, we demonstrated that sugars drive the synthesis of ammonia from nitrite [9]. The ability of sugars to drive ammonia synthesis provides a way to generate ammonia at microscopic sites of sugar-based origins processes, thereby eliminating the need for a planet-wide source of photochemically unstable ammonia.

Figure 1. Major Synthetic Processes of Abiogenesis.

[1] Weber A. L. (1998) Orig. Life Evol. Biosph., 28, 259-270. [2] Weber A. L. (2001) Orig. Life Evol. Bi- osph., 31, 71-86. [3] Weber A. L. (2002) Orig. Life Evol. Biosph., 32, 333-357. [4] Weber A. L. (2004) Orig. Life Evol. Biosph., 34, 473-495. [5] Weber A. L. (2005) Orig. Life Evol. Biosph., 35, 523-536. [6] We- ber A.L. and Pizzarello S. (2006) Proc. Nat. Acad. Sci. USA, 103, 12713-12717. [7] Weber A. L. (2007) Orig. Life Evol. Biosph., 37, 105-111. [8] Weber A. L. (2008) Orig. Life Evol. Biosph., 38, 279-292. [9] We- ber A. L. (2009) Orig. Life Evol. Biosph., in press.