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Abiogenesis enigma: Protein’s origin

Proteins

As you might know, proteins are one of the major “building blocks” of cells; there’s up to 10.000 different types of proteins, all manufactured inside each cell. Abiogenesis theorists  obviously supports the view that these molecules have arisen “by chance”, in a prebiotic world, billion years ago, however, to date, they have absolutely no clue about it, as we can read from this article:

“Proteins are the most complex chemicals synthesized in nature and must fold into complicated three-dimensional structures to become active. This poses a particular challenge in explaining their evolution from non-living matter. So far, efforts to understand protein evolution have focused on domains, independently folding units from which modern proteins are formed. Domains however are themselves too complex to have evolved de novo in an abiotic environment. We think that domains arose from the fusion of shorter, non-folding peptides, which evolved as cofactors supporting a primitive, RNA-based life form (the ‘RNA world’).” 1

So, why is it so complicated to explain its origin? Despite the often repeated innuendo that life and all of its components has “assuredly” originated through natural means, the clear failure of scientists to solve this puzzle can be easily explained by some truths about proteins, its synthesis, structure and so on. After that, no one can reasonably take its abiogenetic origin as logically granted. These truths also explain without shadow of doubt the intriguing fact that absolutely no single protein (even the lesser one, composed of only 8 amino acids) has ever been observed to appear anywhere in the world, outside the cells and high-tech labs, of course!

What’s a protein?

“Proteins are large biological molecules consisting of one or more chains of amino acids. Proteins perform a vast array of functions within living organisms, including catalyzing metabolic reactionsreplicating DNAresponding to stimuli, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in folding of the protein into a specific three-dimensional structure that determines its activity.

A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of adjacent amino acid residues. The sequence of amino acids in a protein is defined by the sequence of a gene, which is encoded in the genetic code. In general, the genetic code specifies 20 standard amino acids;” 2

Talking about amino acids, we’d like to recall another crucial problem for abiogenesis: The absence of self-occurring homochiral mixtures. As it has been told in a previous article, the laws of thermodynamics obliges the occurrence of racemic mixtures, ever:

“The left and right handed forms have identical free energy (G), so the free energy difference (ΔG) is zero. The equilibrium constant for any reaction (K) is the equilibrium ratio of the concentration of products to reactants. The relationship between these quantities at any Kelvin temperature (T) is given by the standard equation:

K = exp (–ΔG/RT)

where R is the universal gas constant (= Avogadro’s number x Boltzmann’s constant k) = 8.314 J/K.mol.

For the reaction of changing left-handed to right-handed amino acids (L → R), or the reverse (R → L), ΔG = 0, so K = 1. That is, the reaction reaches equilibrium when the concentrations of R and L are equal; that is, a racemate is produced.”

Therefore, any abiogenetic theorist has this astounding problem to deal with from the very beginning; without homochiral monomers, we can have zero possibility of a ‘magic’ protein self-assembling…

 

Protein synthesis

 

It’s quite uncanny that intelligent people with advanced knowledge on the subject might attempt to conceive hypothesis of such molecules originating spontaneously, in the wild and morbid inorganic environment, because for cells to build proteins, an intricate, complex and laborious process must take place!

 

 

First, genetic information is needed:

“Proteins are assembled from amino acids using information encoded in genes. Each protein has its own unique amino acid sequence that is specified by the nucleotide sequence of the gene encoding this protein. The genetic code is a set of three-nucleotide sets called codons and each three-nucleotide combination designates an amino acid (for example AUG (adenineuracilguanine) is the code for methionine).”

 

Many proteins use more that one of the 64 possible codons to be built. Moreover, that specific genetic code must be first translated, transcribed:

“Genes encoded in DNA are first transcribed into pre-messenger RNA (mRNA) by proteins such as RNA polymerase. Most organisms then process the pre-mRNA (also known as a primary transcript) using various forms of Post-transcriptional modification to form the mature mRNA, which is then used as a template for protein synthesis by the ribosome.”

Oh great, a bit complicated, isn’t it? Please, read the Wikipedia article referring to the messenger RNA, for further comprehension of what it is, its manufacturing, composition, etc; all of which adds up more complexity for the protein origin’s explanation.

 

 

The process of synthesizing a protein from an mRNA template is known as translation. The mRNA is loaded onto the ribosome and is read three nucleotides at a time by matching each codon to its base pairing anticodon located on a transfer RNA molecule, which carries the amino acid corresponding to the codon it recognizes. The enzyme aminoacyl tRNA synthetase “charges” the tRNA molecules with the correct amino acids. The growing polypeptide is often termed the nascent chain. Proteins are always biosynthesized from N-terminus to C-terminus.[6]

The size of a synthesized protein can be measured by the number of amino acids it contains and by its total molecular mass, which is normally reported in units of daltons (synonymous with atomic mass units), or the derivative unit kilodalton (kDa). Yeast proteins are on average 466 amino acids long and 53 kDa in mass.[5] The largest known proteins are the titins, a component of the muscle sarcomere, with a molecular mass of almost 3,000 kDa and a total length of almost 27,000 amino acids.[8]

 

Phew! How complicated! You may ask now: are we finally done? And I reply you: Huh, nope! Now that the ribosome, together with the rRNA and more than 50 other proteins, has finally finished the process, a protein is formed. However, it is always found in a  random coil shape. So what? This shape is mostly useless for its usage on organism, as we can read:

Each protein exists as an unfolded polypeptide or random coil when translated from a sequence of mRNA to a linear chain of amino acids. This polypeptide lacks any stable (long-lasting) three-dimensional structure (the left hand side of the neighbouring figure). 3

In that randomly coiled shape, the protein is highly unstable, breakable, useless for cell building, so, for proper biological use and better stability, the protein folding process must take place. This 3D-shape is known as the native state.

The correct three-dimensional structure is essential to function, although some parts of functional proteins may remain unfolded.[4] Failure to fold into native structure generally produces inactive proteins, but in some instances misfolded proteins have modified or toxic functionality. Several neurodegenerative and other diseases are believed to result from the accumulation of amyloid fibrils formed by misfolded proteins.[5] Many allergies are caused by incorrect folding of some proteins, for the immune system does not produce antibodies for certain protein structures.[6]

Another importance of the protein folding is:

 

Minimizing the number of hydrophobic side-chains exposed to water is an important driving force behind the folding process.[9] Formation of intramolecular hydrogen bonds provides another important contribution to protein stability.[10] 

 

And how does the folding occurs?

 

 

The amino-acid sequence of a protein determines its native conformation.[7] A protein molecule folds spontaneously during or after biosynthesis. While these macromolecules may be regarded as “folding themselves“, the process also depends on the solvent (water or lipid bilayer),[8] the concentration of salts, the pH, the temperature, the possible presence of cofactors and of molecular chaperones.

The process of folding often begins co-translationally, so that the N-terminus of the protein begins to fold while the C-terminal portion of the protein is still beingsynthesized by the ribosome. Specialized proteins called chaperones assist in the folding of other proteins.

Although most globular proteins are able to assume their native state unassisted, chaperone-assisted folding is often necessary in the crowded intracellular environment to prevent aggregation; chaperones are also used to prevent misfolding and aggregation that may occur as a consequence of exposure to heat or other changes in the cellular environment.

There are two models of protein folding that are currently being confirmed: The first: The diffusion collision model, in which a nucleus is formed, then the secondary structure is formed, and finally these secondary structures are collided together and pack tightly together. The second: The nucleation-condensation model, in which the secondary and tertiary structures of the protein are made at the same time. Recent studies have shown that some proteins show characteristics of both of these folding models.

The essential fact of folding, however, remains that the amino acid sequence of each protein contains the information that specifies both the native structure and the pathway to attain that state. Folding is a spontaneous process independent of energy inputs from nucleoside triphosphates. The passage of the folded state is mainly guided by hydrophobic interactions, formation of intramolecular hydrogen bonds, and van der Waals forces, and it is opposed by conformational entropy.

Only after the folding process, we have an useful, stable protein, with a properly designed shape with its up to four layers, so that the molecule can perform its biological function.

But, remember, many conditions and external factors can destroy proteins, such as hydrolysis (it’s a slow, but ceaseless process, because proteins are metastable, hydrophobic) and others:

Under some conditions proteins will not fold into their biochemically functional forms. Temperatures above or below the range that cells tend to live in will cause thermally unstableproteins to unfold or “denature” (this is why boiling makes an egg white turn opaque). High concentrations of solutes, extremes of pH, mechanical forces, and the presence of chemical denaturants can do the same.

A fully denatured protein lacks both tertiary and secondary structurel. Under certain conditions some proteins can refold; however, in many cases, denaturation is irreversible.[15] Cells sometimes protect their proteins against the denaturing influence of heat with enzymes known as chaperones or heat shock proteins, which assist other proteins both in folding and in remaining folded. Some proteins never fold in cells at all except with the assistance of chaperone molecules, which either isolate individual proteins so that their folding is not interrupted by interactions with other proteins or help to unfold misfolded proteins, giving them a second chance to refold properly. This function is crucial to prevent the risk of precipitation into insoluble amorphous aggregates.

 

For a further an in-depth study about different factors capable of disrupting proteins, read the following articles:

https://en.wikipedia.org/wiki/Protein_biosynthesis

http://creation.com/native-folds-in-polypeptide-chains-1 (a series of 6 parts)

 

To conclude our observation, it’s impossible not to be sceptic of any theoretic proposition that claims self-caused origin of proteins, because it turns out that science unveiled tons of facts that easily prevent any possibility of such proposed scenario:

 

-Absence of homochiral monomers forming in the environment;

-Necessity of genetic specific information;

-Need for an highly controlled ambient, with proper Ph level, temperature, absence of mechanical forces that may easily damage, disrupt the protein, toxins, etc; 

-Need for specific methods to protect the protein against hydrolysis, oxidation;

-Necessity of having 50 other types of protein already manufactured to help on the protein synthesis;

 

The question raises: how in the world could such a specific set of conditions be found in a prebiotic Earth? Such condition can only be barely found in a first-class laboratory, driven by qualified and experienced scientists!

You might as well enjoy watching this short video talking about protein synthesis:

 

References

1. <http://www.eb.tuebingen.mpg.de/research/departments/protein-evolution/protein-evolution.html>

2. <https://en.wikipedia.org/wiki/Protein>

3. <https://en.wikipedia.org/wiki/Protein_folding>

ATP-synthase: wonderful molecular machine

Today, we’re going to talk about an absolutely wonderful biological machine, called ATP-synthase, another marvel built on almost every living beings that fascinates and intrigues naturalistic minds! Again, to conceive that such a intricate system could have arisen after random mutations defies logic.  But, unfortunately, nothing prevents evolutionists to contrive the most bizarre hypothesis with the purpose of giving the credits to chance, nothingness again.

ATP Synthase is a molecular machine found in every living organisms. It serves as a miniature power-generator, producing an energy-carrying molecule, adenosine triphosphate, or ATP. The ATP synthase machine has many parts we recognize from human-designed technology, including a rotor, a stator, a camshaft or driveshaft, and other basic components of a rotary engine. This machine is just the final step in a long and complex metabolic pathway involving numerous enzymes and other molecules—all so the cell can produce ATP to power biochemical reactions, and provide energy for other molecular machines in the cell. Each of the human body’s 14 trillion cells performs this reaction about a million times per minute. Over half a body weight of ATP is made and consumed every day!

ATP-driven protein machines power almost everything that goes on inside living cells, including manufacturing DNA, RNA, and proteins, clean-up of debris, and transporting chemicals into, out of, and within cells. Other fuel sources will not power these cellular protein machines for the same reasons that oil, wind, or sunlight will not power a gasoline engine.

ATP synthase occurs on the inner membranes of bacterial cells, and the innermost membranes of both mitochondria and chloroplasts, which are membrane-bound structures inside animal and plant cells.

ATP synthase manufactures ATP from two smaller chemicals, ADP and phosphate. ATP synthase is so small that it is able to manipulate these tiny molecules, one at a time. ATP synthase must convert some other form of energy into new ATPs. This energy is in the form of a hydrogen ion (H+) gradient, which is generated by a different whole protein system to ATP synthase. Hydrogen ions pour through ATP synthase like wind through a windmill. This comprises a positively charged electric current, in contrast to our electric motors, which use a negative current of electrons.

ATP synthase is a complex engine and pictures are necessary to describe it. Scientists use clever techniques to resolve the exact locations of each of many thousands of atoms that comprise large molecules like ATP synthase. This protein complex contains at least 29 separately manufactured subunits that fit together into two main portions: the head and the base. The base is anchored to a flat membrane like a button on a shirt (except that buttons are fixed in one place, whereas ATP synthase can migrate anywhere on the plane of its membrane). The head of ATP synthase forms a tube. It comprises six units, in three pairs. These form three sets of docking stations, each one of which will hold an ADP and a phosphate. ATP synthase includes a stator (stationary part), which arcs around the outside of the structure to help anchor the head to the base.

 F1-ATPase

F1-ATPase

Notice in figure 1 a helical axle labeled “γ” in the middle of the ATP synthase. This axle runs through the center of both the head and base of ATP synthase like a pencil inside a cardboard toilet paper tube.

Here is the “magic”: When a stream of tiny hydrogen ions (protons) flows through the base and out the side of ATP synthase, passing across the membrane, they force the axle and base to spin. The stiff central axle pushes against the inside walls of the six head proteins, which become slightly deformed and reformed alternately. Each of your trillions of cells has many thousands of these machines spinning at over 9,000 rpm!

The spinning axle causes squeezing motions of the head so as to align an ADP next to a phosphate, forming ATP … in bucket loads. Many other cellular protein machines use ATP, breaking it down to ADP and phosphate again. This is then recycled back into ATP by ATP synthase. Lubert Stryer, author of Biochemistry adds,

“… the enzyme appears to operate near 100% efficiency …”1

Two Canadian researchers therefore looked into the innermost workings of ATP synthase. Using electron cryomicroscopy, they produced the first-ever three-dimensional representation of all the enzyme’s parts fitted together the way they are in the actual enzyme.1 Their study results, published in the journal Nature, enabled them to reconstruct the specific sequence of timed events that makes the enzyme work. And it’s a good thing that it functions, because every living cell—from bacteria to brain cells—depends on one or another version of ATP synthase.2

The team found two half-channels situated in the base of the motor, forming something like two half-stroke cylinders. The first half-channel directs a single proton to a precise spot on one of the rotor’s 12 segments where a negatively charged oxygen atom receives and temporarily holds it. After spinning 330 degrees on the rotor, the proton re-enters the cylinder assembly through the second half-channel, and is finally released into an area of lower proton concentration. (ICR)

The  F1-ATPase motor

In a paper published in March 1997, Hiroyuki Noji et al. directly observed the rotation of the enzyme F1-ATPase, a subunit of a larger enzyme, ATP synthase. This had been suggested as the mechanism for the enzyme’s operation by Paul Boyer.6 Structural determination by X-ray diffraction by a team led by John Walker had supported this theory. A few months after Noji et al published their work, it was announced that Boyer and Walker had won a half share of the 1997 Nobel Prize for Chemistry for their discovery.

The F1-ATPase motor has nine components—five different proteins with the stoichiometry of 3a:3b:1g:1d:1e. In bovine mitochondria, they contain 510, 482, 272, 146 and 50 amino acids respectively, so Mr = 371,000. F1-ATPase is a flattened sphere about 10 nm across by 8 nm high—so tiny that 1017 would fill the volume of a pinhead. This has been shown to spin ‘like a motor’ to produce ATP, a chemical which is the ‘energy currency’ of life. This motor produces an immense torque (turning force) for its size—in the experiment, it rotated a strand of another protein, actin, 100 times its own length. Also, when driving a heavy load, it probably changes to a lower gear, as any well-designed motor should.

ATP synthase also contains the membrane-embedded FO subunit functioning as a proton (hydrogen ion) channel. Protons flowing through FO provide the driving force of the F1-ATPase motor. They turn a wheel-like structure as water turns a water wheel, but researchers are still trying to determine precisely how. This rotation changes the conformation of the three active sites on the enzyme. Then each in turn can attach ADP and inorganic phosphate to form ATP. Unlike most enzymes, where energy is needed to link the building blocks, ATP synthase uses energy to link them to the enzyme, and throw off the newly formed ATP molecules. Separating the ATP from the enzyme needs much energy. (CMI)

Evolutionists’ reverie

Evolutionary scientists have suggested that the head portion of ATP synthase evolved from a class of proteins used to unwind DNA during DNA replication, i.e, the hexameric helicase enzyme. 3

However, how could ATP synthase “evolve” from something that needs ATP, manufactured by ATP synthase, to function? Absurd “chicken-egg” paradox! Also, consider that ATP synthase is made by processes that all need ATP—such as the unwinding of the DNA helix with helicase to allow transcription and then translation of the coded information into the proteins that make up ATP synthase. And manufacture of the 100 enzymes/machines needed to achieve this needs ATP! And making the membranes in which ATP synthase sits needs ATP, but without the membranes it would not work. This is a really vicious circle for evolutionists to explain.

Some says that not every living beings need ATP-synthase, such as anaerobical bacteria, because they produce ATP via glycolysis only. Thus, they imply that evolution really occurred on the creation of ATP-synthase… But every organism need ATPase!

Obligate anaerobes may not use ATP synthase to manufacture ATP, but they do use it to pump protons out of their cytoplasm. They would die otherwise. All cells have ATP synthase, because all cells need it. In sum, all life depends on ATPase, but not all life depends on it for ATP production. Anaerobic bacteria use it to maintain pH balance instead. So ATPase must have been present in the very first cell.

As the researches advance, more impressive facts are disclosed! The necessity of engineering  ATPase is actually just the tip of the iceberg. One amazingly revealing 2010 study in the journal Nature demonstrated how not only ATPase, but the entire electron transport chain apparatus and in fact whole mitochondria were absolutely essential to the ‘first’ eukaryote. 4

So, the evolutionary dilemma only strengthens! Oh, surely they miss the Darwin’s epoch, when cells were just organic “jellybeans”, which no complex content, the eye anatomy was the most complicated biological mechanism they’ve had to deal with (and even the contemporary knowledge of eye was enough to puzzle Darwin’s mind!), there was no annoying DNA (with its smart informational content pointing to a intelligent Creator), second Laws of Thermodynamics denying spontaneous increasing in complexity of polymers occurring naturally, and so on… Damn it, science, always disturbing godless people dreams!

References

______________________________________________

1 Stryer. L., Biochemistry, 18.4.3., The world’s smallest molecular motor: rotational catalysis, online: <www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=stryer.section.2528# 2539>.

2 Lau, W. C. Y. and J. L. Rubinstein. 2012. Subnanometre-resolution structure of the intact Thermus thermophilus H+-driven ATP synthase. Nature. 481 (7380): 214-218.

3 Evolution of the F1-ATPase <www.life.uiuc.edu/crofts/bioph354/Evol_F1.html>.

4 Lane, N. and W. Martin. 2010. The energetics of genome complexity. Nature. 467 (7318): 929-934.

Also:

http://creation.com/atp-synthase-in-all-life

http://creation.com/design-in-living-organisms-motors-atp-synthase

 

God bless you!

“I will praise thee; for I am fearfully and wonderfully made: marvellous are thy works; and that my soul knoweth right well.” Psalms 139.14

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