Protein Amino acid change

The appearance of weeds that showed considerable resistance to the triazine herbicides eventually led to detailed biochemical studies that identified resistance mechanisms at the level of a D1 protein amino acid change. Hirschberg and Mclntosh showed that in Amaranthus hybridus this was due to a replacement of serine 264 by glycine. Remarkably, this particular amino acid change did not greatly affect the inhibitory properties of the phenylurea diuron. Subsequent work has shown, however, that changes at amino acids 219 and 275 will give resistance to diuron but have... 

T. Kohno, D. Kohda, M. Haruki, S. Yokoyama, and T. Miyazawa, Non-protein amino acid furanomycin, unlike isoleucine in chemical structure, is changed to isoleucine tRNA by isoleucyl-tRNA synthetase and incorporated into protein. J. Biol. 

These minimalistic peptide scaffolds potentially provide a biologically relevant laboratory in which to explore the details of heme-peptide interactions and, with development, perhaps approach the observed range of natural heme protein fimction. These heme-peptide systems are more complex than typical small molecule bioinorganic porphyrin model compoimds, and yet are seemingly not as enigmatic as even the smallest natural heme proteins. Thus, in the continuum of heme protein model complexes these heme-peptide systems lie closer to, but certainly not at, the small molecule limit which allows for the effects of single amino acid changes to be directly elucidated. 

Substrate specificity between DHK, DHQ, and DHM appears, based on chimeric DFR proteins formed using the P. hybrida and Gerbera hybrida sequences, to locate to a 26 amino acid region that may be the binding pocket for the B-ring, and as little as one amino acid change in this region can alter the specificity of the enzyme. ... 

The spectrum of structural mutations that can convert a proto-oncogene into an oncogene is very diverse. Both simple amino acids changes in the coded protein and larger structural changes are observed. In particular, viral oncoproteins demonstrate multiple mutations compared to their cellular coimterparts, linked to important and far-reaching structural and fimctional changes. 

Mutations that lead to amino acid changes in transferrin may alter the charge of the protein, thereby leading to shifts in the IEF pattern, which mostly resemble to either... 

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