Proteinoides también referidos como proteínas térmicas, polímeros térmicos de aminoácidos[1] o moléculas heterocomplejas térmicas de los aminoácidos[2] son agregados, similares a las proteínas,
formados abióticamente por aminoácidos, ácidos nucleicos y compuestos inorgánicos. Sidney Fox desarrolló un trabajo pionero en la síntesis de polipéptidos térmicos. Fox calentó mezclas secas de 16 a 18 aminoácidos en 160-180 º en una atmósfera de nitrógeno durante un período de tiempo de varias horas.[3] Notó que los aminoácidos se hicieron unidos entre sí por la pérdida de moléculas de agua. Fox nombró a los productos resultantes de la síntesis "proteinoides".[4] If proteinoids are dissolved in boiling water and the the solution is cooled the proteinoid molecules will coalesce to form microspheres.[5] The theory of abiogenesis proposed by Sidney Fox in the '60s, and who does not find many followers in the scientific community nowadays,[6] stated that the agglomeration of proteinoid microspheres would have given rise to the precursors of the first living cells. Fox claimed that his proteinoid microspheres constitute protocells which were a vital link between the primordial chemical environment and true living cells.[7]
Comparison between true proteins and proteinoids
Spontaneous combinations of biomonomers may lead to proteinlike substances called proteinoids.[8] Proteinoids are not fully functioning proteins. The following table illustrates some of the major differences:
Characteristic
|
Proteinoid
|
True protein
|
Type of chain
|
Unnatural chains, “kinked” chains, even branched chains instead of being linear are produced[5][9] Secondary peptide linkages through the non-alpha carboxyl groups of aspartic and glutamic acids can be expected.[10]
|
Linear
|
Peptide bonds
|
β, γ and ε peptide bonds largely predominate over α-peptide bonds[4]
|
α-peptide bonds
|
Form of amino acids
|
Roughly the same number of D-amino acids (right-handed) and L-amino acids (left-handed).[4][5] Even if the experiment begins will all L-amino acids, some are converted to the right-handed form[9] and the L-amino acids undergo racemic[10]
|
Only L-amino acids
|
Coding sequences
|
Amino acids bond together randomly.
|
Amino acids bond together based on the code contained in DNA.
|
Pigments
|
Some amino acids are converted to colored substances, pigments, which are incorporated into the chains.[9]
|
Amino acids remain as is without converting to pigments
|
Antigenicity tests
|
Show no antigenicity with guinea pig, rabbit or uterine strip tests[8]
|
Proteins (generally with a molecular weight of at least 8,000 Da) show antigenicity in tests
|
See also
Referencias
- ↑ Dose, Klaus; Rauchfuss, Horst (1972). «On the Electrophoretic Behavior of Thermal Polymers of Amino Acids». En Rohlfing, Duane L.. Molecular Evolution: Prebiological and Biological. Springer. p. 199-217. ISBN 978-1-4684-2021-0. http://link.springer.com/chapter/10.1007/978-1-4684-2019-7_17.
- ↑ Haruna, Taichi; Shiozaki, Junya; Tanaka, Sayaka (11 2012). Umano, M. et al.. ed. «How Does Thermal Gradient Contribute to Microcapsule Formation by Proteinoids?». Proceedings of the 6th International Conference on Soft Computing and Intelligent Systems and 13th International Symposium on Advanced Intelligent Systems: p. 2314-2316. http://e-zerde.kz/kobe/papers/short/72.pdf.
- ↑ Davis, Percival; Kenyon, Dean H. Of Pandas and People: The Central Question of Biological Origins (2ª edición). Dallas, Texas: Haughton Publishing Company. p. 51-52. ISBN 0-914513-40-0.
- ↑ 4,0 4,1 4,2 Thaxton, Charles B.; Bradley, Walter L.; Olsen, Roger L (1984). The Mistery of Life's Origin: Reassessing Current Theories. New York: Philosophical Library. p. 155-156. ISBN 0-8022-2447-4.
- ↑ 5,0 5,1 5,2 Plantilla:Cite book
- ↑ Berlinski, David (209). The Deniable Darwin and Other Essays. Seattle: Discovery Institute Press. p. 126-127. ISBN 978-0-9790141-2-3.
- ↑ Plantilla:Cite journal
- ↑ 8,0 8,1 Plantilla:Cite book
- ↑ 9,0 9,1 9,2 Plantilla:Cite book
- ↑ 10,0 10,1 Plantilla:Cite book