Originally posted by DNAunion DNAunion: BBBZZZZZTTTT! Wrong!
Sounding a hypothetical buzzer doesn't make your assertions right. It's only purpose is to annoy, not discuss. So from now on I'll ignore them.
All you arguments are based upon modern-day cells. This is what
some cells look like -- modern ones. But to say then that
all cells
must look like this is invalid.
Heating amino acids gives you PROTEINOIDS, NOT PROTEINS. (I have a long list of differences in my personal notes that I will post if anyone is interested, but for now I will simply say that proteinoids are not proteins).
Go ahead and post them, but the proteinoids are proteins. Proteins are polymers of amino acids. That is what proteinoids are. The reason Fox chose the different name was not because the proteinoids aren't proteins, but to distinguish proteins made by thermal condensation from proteins made from directed synthesis from nucleic acid. It's a cute semantic quibble, but nothing more than that.
DNAunion: Cells contain nucleic acids you cant have a cell with just proteins.
Sure you can. Here you are asserting your bias in order to exclude protocells from being cells.
The outter boundary (or one of the outer boundaries) of cells is a phosopholipid bilayer you cant have a cell with just proteins.
The cell membrane of contemporary cells is over 60% protein. NOW. The rest is lipid, but all that is required is the semipermeable membrane, and proteins give you that just as well as lipid.
Cells have internal growth and actively replicate - do your "cells" do that?
They have internal growth by the formation of new proteins from amino acids. Catalyzed by the enzymatic activity of the proteins. They also grow by accretion or absorption of nutrients and other proteins. So what? No one says that all cells have to grow by the methods of modern day cells. Protocells reproduce by 4 mechanisms. Again, no one says -- except those who have a bias to exclude protocells -- that all cells have to reproduce by the same mechanisms as modern day cells.
(I have a long list of differences in my personal notes that I will post if anyone is interested, but for now I will simply say that proteinoid microsphere are not cells).
Again, go ahead and post them. Actually, you have posted most of them already, and they are irrelevant to the claim that protocells are alive.
No one has produced under prebiotically plausible conditions proteins that catalyze the chemical reactions of life.
Lets take proteins that catalyze the chemical reaction of life [that involves] the breakdown of chemicals to release energy in their chemical bonds. How about glycolysis? Show us valid material with full references - to prebiotic experiments that produced all the 10 (IIRC) proteins that catalyze glycolysis.
Again, you don't have to have glycolysis. You have to have catabolism -- breaking down compounds for energy -- and anabolism -- building new compounds. The protocells have both. you can see a list of some of the enzymatic activities at
http://www.theharbinger.org/articles/rel_sci/fox.html
Lets take proteins that catalyze the chemical reaction of life [that involves the] formation of
nucleic acids. Show us valid material with full references to experiments that produced a protein that could form RNA or DNA from their precursors, all of which occurred under prebiotically plausible conditions.
OK.
6. SW Fox, JR Jungck, T Nakashima, From proteinoid microsphere to contemporary cell: formation of internucleotide and peptide bonds by proteinoid particles. Origins of Life 5: 227-237, 1974.
7. T Nakashima and SW Fox, Synthesis of peptides from amino acids and ATP with lysine-rich proteinoid. J. Molecular Evolution 15: 161-168, 1980.
11. JR Jungck and SW Fox, Synthesis of oligonucleotides by proteinoid microspheres acting on ATP. Naturwissenschaften, 60: 425-427, 1973.
12. T Nakashima and SW Fox, Synthesis of peptides from amino acids and ATP with lysine rich proteinoid. J. Mol. Evol. 15: 161-168. 1980.
As to plausible prebiotic conditions, remember that protocells are being formed
now at undersea hydrothermal vents. Fox has also shown that protocells form on lava and in a wide variety of atmospheres.
11. Origin of life: a sulfurous start for protein synthesis? Science 281: 627-628, 1998 (31 July). Full paper C Huber and G. Wachterhauser, Peptides by activation of amino-acids with CO on (NiFe)S surfaces: implications for the origin of life. Science 281: 670-672, 1998 (31 July).
10. SW Fox, Thermal polymerization of amino-acids and production of formed microparticles on lava. Nature, 201: 336-337, Jan. 25, 1964.
Biosystems 1976 Jul;8(2):45-50 Formation of proteinoid microspheres under simulated prebiotic atmospheres and individual gases. McAlhaney WW, Rohlfing DL.
There's also a paper showing protocells forming in simulated tidal pools. I'll get that one for you.
DNAunion: You mean youve actually solved the puzzle of the abiotic origin of homochirality? Thats been a longstanding mystery of prebiotic chemistry.
I didn't solve it, but there are several solutions out there if you would take the time to look.
1. FASEB J 1998 Apr;12(6):503-507 RNA-directed amino acid homochirality. Martyn Bailey J
2. Chirality Volume 9, Issue 2 <Picture>Abstract 1997 Pages 99-102. The nature of chiral recognition: Is it a three-point interaction? Davankov V.A. 3.
3. Z Naturforsch [C] 1997 Jan;52(1-2):89-96
Plural origins of molecular homochirality in our biota Part II. The relative stabilities of homochiral and mixed oligoribotides and peptides. Soares TA, Lins RD, Longo R, Garratt R, Ferreira R This one shows that mixed chiral proteins also function, so making the initial proteinoids in a heterochiral environment ceases to be a problem.
4. J Biochem (Tokyo) 1993 Aug;114(2):177-180
Substrate specificity of protein kinase C studied with peptides containing D-amino acid residues. Eller M, Jarv J, Toomik R, Ragnarsson U, Ekman P, Engstrom L
Remember, many proteins in organisms
now contain D-amino acids. This is especially true in bacterial cell walls.
