Single-site binding

It has been known for some time that tetracyclines are accumulated by bacteria and prevent bacterial protein synthesis (Fig. 4). Furthermore, inhibition of protein synthesis is responsible for the bacteriostatic effect (85). Inhibition of protein synthesis results primarily from dismption of codon-anticodon interaction between tRNA and mRNA so that binding of aminoacyl-tRNA to the ribosomal acceptor (A) site is prevented (85). The precise mechanism is not understood. However, inhibition is likely to result from interaction of the tetracyclines with the 30S ribosomal subunit because these antibiotics are known to bind strongly to a single site on the 30S subunit (85). 

It is surprising that data on natural particles can be fitted over a range of concentrations (representative of those encountered in natural waters) on the basis of a "single-site" surface complex formation model. Apparently similar types of binding groups are predominant and of importance in these particles. 

Thus structural background suggests that the bound cyt c ccp adduct may actually consist of a distribution of structures. In this section, we consider the thermodynamics of binding cyt c and ccp, both for the native proteins, from different species, and proteins incorporating single site replacements, as prepared by site directed mutagenesis. 

Finally, we consider the effects on recognition and binding of single site replacements [34] of the individual charged residues which have been emphasized in molecular modeling studies. These residues include Lys (18, 32, 77) in cytochrome c and Asp (37, 79, 217) in ccp. 

Adsorption on a Single-Site Polymer with Conformational Changes Induced by the Binding Process... 

One of our main assumptions in the derivation of the Langmuir model [and implicitly made by Langmuir himself (1918)] is that the binding process does not affect the distribution of states of the adsorbent molecules. Removal of this assumption has a profound effect on the form of the BI of systems with more than a single site. 

In this section we find it more convenient to start with an ensemble of M independent and indistinguishable systems (i.e., the systems are identical but not localized, as assumed in Section 2.4), each of which has a single binding site. We stress from the outset that the concept of cooperativity, as defined in Section 4.2, does not apply to such systems. What we shall show is that under certain conditions a single-site system can exhibit behavior that is similar to the behavior of a cooperative system. 

See footnote p. 65 in Section 3.5. It is possible that the two forms L and H will be very similar, i.e., Ql = Qn, hence Eq. (4.6.6), but the binding properties of L and H differ widely. The analytical study of the case Xl Xh is possible but quite involved. In Appendix F we discuss this aspect for a single-site system. 

Mixture of three different single-site molecules. In the previous examples we discussed two-state systems of L and H. These could be either a mixture of two components, or a mixture obtained by freezing-in an equilibrium between two states. We extend the discussion to three states, denoted by L, H, and T, with corresponding binding constants k, and kj. 

Thus, k is the intrinsic binding constant for the site a, while kab is the intrinsic binding constant for the pair of sites a and b. When the sites are identical, then one should take care to distinguish between the thermodynamic (sometimes referred to as macroscopic) constant Ky, which is the binding constant to the rsr site, and the intrinsic (sometimes referred to as microscopic) binding constant Ky/2, which refers to a specific single site. In the case of two different sites, the thermodynamic first constant, as measured from the total BI, is simply k + k. ... 

Single-site amino acid alterations were carried out to show that mutations in the T1 domain loop region disrupt p subunit binding to the a subunit and abolish inactivation. Similar mutations on the p subunit surface that contacts the T1 domain also affected inactivation. The conclusion is that both subunits are necessary for inactivation peptides to carry out their function. 

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