Bell S D, Denu J M, Dixon J E, Ellington A D
Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA.
J Biol Chem. 1998 Jun 5;273(23):14309-14. doi: 10.1074/jbc.273.23.14309.
Protein tyrosine phosphatases (PTPases) are essential proteins in many cellular processes. In vitro selection was used to evolve high affinity RNA aptamers to the Yersinia PTPase from two random pools varying in length. Selected aptamers from the two different pools share a 21-residue conserved sequence. They bind to their target with dissociation constants of 18 and 28 nM and inhibit the enzyme with IC50 values of 10 and 35 nM, but do not bind a related PTPase. Modification of the PTPase's active site cysteine with the alkylating agent iodoacetate results in a loss of binding affinity. These experiments suggest that the selected aptamers act by binding at or near the active site and might therefore be useful in defining the interactions between PTPases and their targets.
蛋白酪氨酸磷酸酶（PTPases）是许多细胞过程中的重要蛋白质。利用体外筛选从两个长度不同的随机文库中进化出针对耶尔森氏菌PTPase的高亲和力RNA适体。从两个不同文库中选出的适体共有一个21个残基的保守序列。它们与靶标的解离常数分别为18和28 nM，对该酶的抑制IC50值分别为10和35 nM，但不与相关的PTPase结合。用烷基化剂碘乙酸修饰PTPase的活性位点半胱氨酸会导致结合亲和力丧失。这些实验表明，所选适体通过在活性位点或其附近结合发挥作用，因此可能有助于确定PTPases与其靶标之间的相互作用。
