Electroweak Parity-Violating Energy Shifts of Amino Acids: The ``Conformation Problem''

Details Electroweak Parity-Violating Energy Shifts of Amino Acids: The ``Conformation Problem'' Electroweak Parity-Violating Energy Shifts of Amino Acids: The ``Conformation Problem''

Mar 2009

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009oleb..tmp....5m&link_type=abstract

Origins of Life and Evolution of Biospheres, Online First

Statistics

Computation

1

Chirality, Homochirality, Parity-Violating Energy Shift, Pved, Pves, L-Alanine

Scientific paper

The preceding paper described our coupled-perturbed Hartree-Fock (CPHF) and density functional theory (DFT) methods of computing the parity-violating energy shift (PVES). This paper addresses the “conformation problem”—the difficulty determining which hand of amino acids in solution is favoured by the weak force due to the difficulty determining the solution conformation. We attempt to resolve this by using the methods of the preceding paper to compute the PVES of solution and gas-phase amino acid structures determined by other groups from high level optimizations that include solvation. We conclude that the conformational hypersensitivity of the PVES still precludes a definite conclusion as to the sign of the PVES of L-alanine in solution, but that there is no problem in the gas phase: the PVES of gas-phase L-alanine is decisively negative. We show that the PVES is very sensitive to certain torsion angles, but is not hypersensitive to bondlengths or bond angles. In determining structures for PVES computations, there is therefore no need for expensive full optimizations: one can just optimize the crucial torsion angles. We present new computations of gas-phase amino acids PVESs, using partial optimizations with small basis sets, and the results agree well with those from higher level techniques. In the following paper we apply these less costly techniques to larger amino acids. The “conformation problem” has led some to dismiss the PVES as the source of life’s handedness, but we believe this is premature: we show here that amino acids are a special case because their favoured conformations are almost achiral.

Affiliated with

Also associated with

No associations

Rating

Electroweak Parity-Violating Energy Shifts of Amino Acids: The ``Conformation Problem'' does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Electroweak Parity-Violating Energy Shifts of Amino Acids: The ``Conformation Problem'', we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electroweak Parity-Violating Energy Shifts of Amino Acids: The ``Conformation Problem'' will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1730353