Structure and function of ribonuclease A binding subsites | 合法醫療器材資訊網

由XParés著作·1991·被引用87次—RibonucleaseAbindsnucleicacidsthroughmultipleelectrostaticinteractionsbetweenthephosphatesofthepolynucleotideandthepositivegroups(side ...

Ribonuclease A binds nucleic acids through multiple electrostatic interactions between the phosphates of the polynucleotide and the positive groups (side chains of lysines and arginines) of the protein subsites. The bases only play a significant role in the binding at the active site. The active centre p1R1B1 sites determine the specificity of the catalytic cleavage. The phosphate-binding subsites p2 (Lys-7 and Arg-10), p1 (Lys-41, His-12 and His-119) and p0 (Lys-66) are essential for an effective catalysis and are conserved in all mammalian pancreatic ribonucleases. Additional phosphate-binding subsites confer further catalytic efficiency, probably by avoiding non-productive binding. The minimum chain size for optimum catalysis is probably longer than six or seven nucleotides. The full occupancy of binding sites by the long chain polynucleotides would explain the preference of the enzyme for these substrates. The m...