Amino unspecific interactions

Because the labeled tetrapeptide does not bind to the unmodified solid support Amino-TentaGel, the observed fluorescence activity is not because of unspecific interaction with the solid support itself. 

At least three regions of the receptor participate in the process of dimer formation. One of them is unspecific and is made up of the sequences of hydrophobic amino acids of the LBD. These form hydrophobic contact surfaces that facilitate, in a general way, the interactions among proteins. The other two are specific sequences of amino acids. One of them is situated immediately after the DBD. It is comprised of a group of some 20 amino acids, and its capacity to intervene in the dimer is independent of binding to the hormone. The other dimerization region is found inside the LBD. It is poorly located, and it is possible that noncontiguous sequences of amino acids participate in it. It is exhibited only when the receptor has been already bound to a hormone. 

Furthermore, from these findings the idea that the rRNA has a catalytic function in the ribosomal peptide bond formation is supported. It can be assumed that the selection of the individual aminoacyl-tRNA for the A site is mostly attributed to the specificity of the appropriate aminoacyl-tRNA synthetase together with the specific codon-anticodon interactions, whereas the 23 S rRNA participates in catalyzing peptide bond formation but without side-chain specificity for the amino acid esterified to the tRNA s 3 -terminal nucleoside. In comparison with the prerequisites for specificity of peptidases the peptidyltransferase seems to be an old unspecific ribozyme in accordance with its function in evolution as precursor to extant life. 

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