Wiele różnych białek u organizmów eukariotycznych ma ‚rozchwiane’ konformacje. Jednak idąc w dół rzekomej drabiny ewolucyjnej uczeni zaobserwowali, że prokarioty mają ściśle ustaloną i wysoce konserwatywną konformację białek. Uczeni wiedzą, że bakteria to jeden worek na wszystkie białka i kwasy nukleinowe, natomiast w komórkach eukariotycznych istnieje wiele wyspecjalizowanych przedziałów komórkowych. Przedziały te chronią różne białka przed wzajemnymi kolizjami i tworzeniem się złogów, co by szybko zabiło komórkę. Bakterii to nie grozi.
Jaki z tego wniosek: taki, że białka u najprostszych organizmów musiały nieć od samego początku ścisle ustaloną konformację. Taki właśnie wniosek wynika z analizy filogenetycznej. Poza tym artykuł wspomina o tym, o czym tutaj dyskutowaliśmy. Podałem namiary na prace naukowe dotyczące rybozymów. Większe rybozymy mogą przyjmować funkcjonalną konformację jedynie przy pomocy białek pomocniczych (chaperonów).
Pojawia się więc kolejny dylemat w rodzaju: „co było pierwsze kura czy jajo”. No i oczywiście jest to kolejny, wymierzony przez prawdziwaą naukę, cios w koncepcję „świata RNA „:
„Dobrze funkcjonujący bałagan”.
‚Świat Nauki’ : 200. 05
Dobrze funkcjonujący bałagan
Podręcznikowa wizja białek aktywnych dopiero po przyjęciu ściśle określonej konfiguracji przestrzennej odchodzi do lamusa. Cząsteczki te nie dają się zamknąć w sztywnych ramach teorii.
A. Keith Dunker i Richard W. Kriwacki
Literatura, która dowodzi tego, że koncepcja Świata RNA jest błędna
Joyce sums up the difficulties of conjuring up a hypothetical RNA world in these words.
“The most reasonable interpretation is that life did not start with RNA … The transition to an RNA world, like the origins of life in general, is fraught with uncertainty and is plagued by a lack of relevant experimental data. Researchers into the origins of life have grown accustomed to the level of frustration in these problems … It is time to go beyond talking about an RNA world and begin to put the evolution of RNA in the context of the chemistry that came before it and the biology that followed.” ( http://www.its.caltech.edu/~bch176/Joyce1989.pdf )
„I looked at the papers published on the origin of life and decided that it was absurd that the thought of nature of its own volition putting together a DNA or an RNA molecule was unbelievable.
I’m always running out of metaphors to try and explain what the difficulty is. But suppose you took Scrabble sets, or any word game sets, blocks with letters, containing every language on Earth, and you heap them together and you then took a scoop and you scooped into that heap, and you flung it out on the lawn there, and the letters fell into a line which contained the words “To be or not to be, that is the question,” that is roughly the odds of an RNA molecule, given no feedback — and there would be no feedback, because it wouldn’t be functional until it attained a certain length and could copy itself — appearing on the Earth.”
Gerald Joyce Experiments have shown That the RNA world hypothesis is stuck on a sandbank. Gerald Joyce finally showed the all possibility of ribozymes;
RNA enzymes have been made to undergo self-sustained replication in the absence of proteins, providing the basis for an artificial genetic system.
An RNA enzyme that catalyzes the RNA-templated joining of RNA was converted to a format whereby two enzymes catalyze each other’s synthesis from a total of four component substrates. These cross-replicating RNA enzymes were optimized so that they can undergo self-sustained exponential amplification at a constant temperature and in the absence of proteins or other biological materials. Amplification occurs with a doubling time of about one hour, and can be continued indefinitely. Populations of various cross-replicating enzymes were constructed and allowed to compete for a common pool of substrates. During a serial transfer experiment in which the population underwent overall amplification of >1025-fold, recombinant replicators arose and grew to dominate the population. RNA enzymes that undergo self-sustained replication can serve as an experimental model of a genetic system. Many such model systems could be constructed, allowing different selective outcomes to be related to the underlying properties of the genetic system.
Gerald Joyce finally showed the possibilities of ribozymes. These experiments showed that the designed by an intelligent person ribozymes and was designed by an intelligent person replication could not lead to the creation of a living cell. Gerald Joyce has shown that these processes can not lead to the evolution of a contemporary living cell. Gerald Joyce showed that all the work of the world of RNA, which are carried out proved to be worthless. The hypothesis of abiogenesis is stuck on a sandbank, and it will never change. The hypothesis of abiogenesis lost to real science! All studies have shown that nar ribozymes, RNA world hypothesis is falsified. Biochemist Gerald Joyce, found that RNA is not suited to the role of the first ingredients of life. Joyce not believes that the world of RNA preceded DNA world, but it is believed that before the RNA had to be some kind of living cells.
RNA World hypothesis assumes that the ribozymes were the precursors of life. However, they have limited ability catalyst. They have the ability ligase and endonuclease. Their greatest achievement to catalyze peptide bond in ribosomes. Multiple ribozymes can accept only a useful conformation by helper proteins (chaperones). These proteins could not be at the start of the evolution of life. So, like a boomerang returns the old question „what came first the chicken or the egg?”
Ribozymes, which are in some way useful to the origin of life, they need to adopt a final protein conformation and useful helpers. Chaperone. Now ask yourself this question: What first appeared RNA (ribozymes) or protein. Question such as „which came first the chicken or the egg?”.
Strategies for RNA folding and assembly
Ren|[eacute]|e Schroeder , Andrea Barta & Katharina Semrad
RNA is structurally very flexible, which provides the basis for its functional diversity. An RNA molecule can often adopt different conformations, which enables the regulation of its function through folding. Proteins help RNAs reach their functionally active conformation by increasing their structural stability or by chaperoning the folding process. Large, dynamic RNA–protein complexes, such as the ribosome or the spliceosome, require numerous proteins that coordinate conformational switches of the RNA components during assembly and during their respective activities.
The phylogenetic analysis shows that the proteins in prokaryotes have from the beginning to have a strictly fixed conformation. Prokaryotes, one bag for everything, if the conformation of the protein would not be fixed from the beginning, it would fall together in a collision. In eukaryotes, where the cellular compartments such stability is not always necessary. Thus, there could be a simple and there was early in the evolution of proteins;
„The whole discussion revolves around one thing: the mystery of RNA molecules in the solution was mixed with each other polynucleotides. From the point of view of chemistry prabiotycznej Such an assumption is not only unrealistic, but also verify Should optimistic views on the potential of catalytic RNA. ”
(GF Joyce, LE Orgel, „Prospects for Understanding the Origin of the RNA World”, In The RNA World, New York: Cold Spring Harbor Laboratory Press, 1993, p 13).
“By applying the strict canons of scientific method to this subject [the spontaneous generation of life], it is possible to demonstrate effectively at several places in the story, how life could not have arisen; the improbabilities are too great, the chances of the emergence of life too small. [….] Regrettably from this point of view, life is here on Earth in all its multiplicity of forms and activities and the arguments have to be bent round to support its existence.”
Professor J. D. Bernal „The Origin of Life”
„More than 30 years of experimentation on the origin of life in the fields of chemical and molecular evolution have led to a better perception of the immensity of the problem of the origin of life on Earth rather than to its solution. At present all discussions on principal theories and experiments in the field either end in stalemate or in a confession of ignorance. New lines of thinking and experimentation must be tried.”
(Dose, Klaus, „The Origin of Life: More Questions Than Answers,” Interdisciplinary Science Reviews, Vol. 13, No. 4, 1988, p.348)