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Protein-based machines mutations

As was discussed in Chapter 5, for Figure 5.17, addition of electrons to a positively charged redox group increases oil-like character and drives model protein folding, which result in contraction and the performance of mechanical work. The increase in affinity for electrons of the vitamin-like molecule that occurs on replacement of Val by Phe (see Figure 5.20C) makes for a more efficient electron-driven contraction. Thus, a genetic code that would allow easy mutational steps to become more oil-like would, here again, provide for evolution of more efficient protein-based machines. [Pg.223]

Mutations and Evolution of Protein-based Machines Table 6.2. The genetic code. [Pg.225]

Changing the second base of two of the four triplet codons for Val, namely, GUA and GUG to GAA and GAG, respectively, are two ways to convert Val to Glu. Changing the second base of the other two triplet codons for Val, for example, GUU to GAU and GUC to GAC, converts Val to Asp. Thus, the Val triplet codons are such that a single base change of the second base from U to A results in amino acid residues with carboxylate side chains. A single mutation converts a thermally driven (and also a poor chemically driven) protein-based machine into a more efficient chemically driven protein-based machine. How trivial and likely the diversification of biology s molecular machines, especially because it costs no more energy (of biosynthesis) to produce the new or improved protein-based machine. [Pg.227]

More to the point, we now see biology s access to energy by means of the consilient mechanism of energy conversion, combined with readily available mutations to improve protein-based machines, as the source of increased structural order and functional diversity. [Pg.229]

As discussed in Chapter 5 and specifically considered in Chapter 6 in relation to evolution, the replacement of a Val residue by a phenylalanine (Phe, F) residue results in a more efficient protein-based machine for chemo-mechanical transduction or for electro-mechanical transduction (see Figures 5.20,5.34, and 5.36 and the associated discussions in Chapter 5). The mutation from Val to Phe occurs with a single base change at the DNA level of guanine to thymine. As listed in Table 6.2, a single base change in position 1 can access a more hydrophobic residue, as in Val to Phe, to provide a more efficient protein-based machine. [Pg.570]


See other pages where Protein-based machines mutations is mentioned: [Pg.218]    [Pg.224]    [Pg.227]    [Pg.227]    [Pg.228]    [Pg.236]    [Pg.569]    [Pg.570]    [Pg.642]    [Pg.315]    [Pg.127]    [Pg.142]    [Pg.154]    [Pg.229]   
See also in sourсe #XX -- [ Pg.224 , Pg.228 , Pg.235 ]




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