85287-46-3Relevant academic research and scientific papers
Aminoacyl-tRNA analogues; synthesis, purification and properties of 3'- anthraniloyl oligoribonucleotides
Nawrot,Sprinzl
, p. 815 - 829 (1998)
Reaction of isatoic anhydride with adenosine, adenosine 5'-phosphate, oligoribonucleotides or with the E. coli tRNA(Val) led to attachment of an anthraniloyl residue at 2'- or 3'-OH groups of 3'-terminal ribose residue. No protection of the 5'-hydroxyl group or internal T-hydroxyl groups is required for this specific reaction. Anthraniloyl-tRNA which is an analogue of aminoacyl-tRNA forms a ternary complex with EF-Tu*GTP. The anthraniloyl- residue is used as a fluorescent reporter group to monitor interactions with proteins.
The strength of the 3′-gauche effect dictates the structure of 3′-O-anthraniloyladenosine and its 5′-phosphate, two analogues of the 3′-end of aminoacyl-tRNA
Acharya, Parag,Nawrot, Barbara,Sprinzl, Mathias,Thibaudeau, Christophe,Chattopadhyaya, Jyoti
, p. 1531 - 1536 (2007/10/03)
Anthranilic acid charged yeast tRNAPhe or E. coli tRNAVal are able to form a stable complex with EF-Tu*GTP, hence the 2′-and 3′-O-anthraniloyladenosines and their 5′-phosphate counterparts have been conceived to be the smallest units that are capable of mimicking aminoacyl-tRNA. Since the 3′-O-anthraniloyladenosine also binds more efficiently to the EF-Tu*GTP complex compared to its 2′-isomer, we have herein delineated the stereoelectronic features that dictate the conformation of 3′-O-anthraniloyladenosine and its 5′-phosphate vis-a-vis their 2′-counterparts and we have also addressed how their structures and thermodynamic stabilizations are different from adenosine and 5′-AMP. It has been found that the electron-withdrawing anthraniloyl group exerts gauche effects of variable strengths depending upon whether it is at the 2′-or at 3′-position because of either the presence or absence of O2′-N9 gauche effect, [GE(O2′-C2′-C1′-N9)]. thereby steering the pseudorotation of the constituent sugar moiety either to the North (N)-type (C3′-endo) or South (S)-type (C2′-endo) conformation. The 3′-O-anthraniloyladenosine 5′-phosphate has a relatively more stabilized S-type conformation ΔG° = -4.6 kJ mol-1) than 3′-O-anthraniloyladenosine itself (ΔC° = -3.9 kJ mol-1), whereas the ΔG° for 2′-O-anthraniloyl-adenosine and its 5′-monophosphate are respectively -0.9 and -1.8 kJ mol-1, suggesting that the 3′-gauche effect of the 3′-O-anthraniloyl group is stronger than that of 2′-O-anthraniloyl in the drive of the sugar conformation. Since the EF-Tu can specifically recognize the aminoacylated-tRNA from the non-charged tRNA, we have assessed the free-energy (ΔG°) for this recognition switch to be the least ≈ -2.9 kJ mol-1 by comparison of ΔG° of the N=S pseudorotational equilibrium for 3′-O-anthraniloyladenosine 5′-phosphate and 5′-AMP. The 3′-O-anthraniloyl-adenosine and its 5′-phosphate are much more flexible than the isomeric 2′-counterparts as is evident from the temperature-dependent coupling constants analysis. The relative rate of the transacylation reaction of 2′(3′)-O-anthraniloyladenosine and its 5′-phosphate is cooperatively dictated by the two-state N=S pseudorotational equilibrium of the sugar, which in turn is controlled by a balance of the stereoelectronic 3′-and 2′-gauche effects as well as by the pseudoaxial preference of the 3′-O-or 2′-O-anthraniloyl group. The reason for the larger stabilization of the 2′-endo conformer for 3′-O-anthraniloyladenosine and its 5′-phosphate lies in the fact that the C3′-O3′ bond takes up an optimal gauche orientation with respect to the C4′-O4′ bond dictating the pseudoaxial orientation of the 3′-anthraniloyl residue, which can be achieved only in the S-type sugar conformation with adenin-9-yl and the 2′-OH groups in the pseudoequatorial geometry, compared to the preferred C3′-endo sugar with a pseudoaxial aglycone and 2′-OH found in the 3′-terminal adenosine moiety in the helical 3′-CCA end of uncharged tRNA.
