Biomaterial Database

Subsite interactions of ribonuclease T1: binding studies of dimeric substrate analogues. 1976

F G Walz, and B Terenna

Ultraviolet difference spectral binding studies of ribonuclease T1 with pGp, ApG, CpG, UpG, DGpdA, dGpdC, dGpdG, dGpdT, dTpdG, pdApdG, pdTpdG, pdGpdA, pdGpdG, pdGpdT, c(pdGpdA), and c(pdGpdG) were conducted at pH 5.0, 0.2 M ionic strength and 25 degrees C. Under these conditions, the characteristic difference spectrum and association constant for (1:1) ribonuclease T1 binding were determined for each ligand. The binding of guanosine and deoxyguanosine containing ligands could be distinguished by the shapes of their difference spectra. The results indicated that the guanine moiety of each ligand was bound at the enzyme's primary recognition site. Evidence of a specific enzyme subsite for binding the adenine moiety of ApG and pdApdG is presented. The proposal of a specific enzyme subsite for binding the 5'-phosphate group of a complexed guanosine moiety (Sawada, F., Samejima, T., and Saneyoshi, M. (1973), Biochim. Biophys. Acta 299, 596) is not supported in the present work. Preliminary evidence for the existence of two additional enzyme subsites and the effect of oligomer conformation on enzyme binding are also discussed.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008024	Ligands	A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)	Ligand
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D006163	Ribonuclease T1	An enzyme catalyzing the endonucleolytic cleavage of RNA at the 3'-position of a guanylate residue. EC 3.1.27.3.	Guanyloribonuclease,RNase T1,Ribonuclease N1,Aspergillus oryzae Ribonuclease,Guanyl-Specific RNase,RNase Apl,RNase F1,RNase Pch 1,RNase ST,Ribonuclease F1,Ribonuclease F2,Ribonuclease ST,Ribonuclease T-1,T 1 RNase,Guanyl Specific RNase,RNase, Guanyl-Specific,RNase, T 1,Ribonuclease T 1,Ribonuclease, Aspergillus oryzae
D012260	Ribonucleases	Enzymes that catalyze the hydrolysis of ester bonds within RNA. EC 3.1.-.	Nucleases, RNA,RNase,Acid Ribonuclease,Alkaline Ribonuclease,Ribonuclease,RNA Nucleases,Ribonuclease, Acid,Ribonuclease, Alkaline
D013056	Spectrophotometry, Ultraviolet	Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Ultraviolet Spectrophotometry