Ribonuclease T1: a model enzyme

RIBONUCLEASE T1 (RNase T1, EC 3.1.27.3) represents a simple but most rewarding model for several purposes: being well-investigated, this enzyme is a target for protein design studies[78], for investigations on structure-function relationships[27,78], folding kinetics[73,62] and dynamic simulations[18]. Furthermore, it has received much attention as a tool in molecular biology, e.g. RNA sequencing[17,76] and mapping[19,58]

Figure 1.1: Stereoimage of a ribonuclease T1$\cdot$2'-GMP complex from 1RNT[3], generated with VMD[36]

RNase T1 is a hydrolase wich hydrolyses a single stranded ribonucleic acid (ssRNA) specifically at the P-O5' ester bond after guanosines. The monomeric enzyme is heat- and acid-stable and very well soluble in water[83]. The enzyme isolated from[2] takadiastase^1.1 occurs in two different isoforms[27] with lysine or glutamine at position 25. Unless indicated otherwise, all data refer to the Lys25 isoform. It has an isoelectric point close to pH 3 and a molecular weight of 11,089 Da (average isotope mass). The cleavage mechanism is supposed to follow a two step mechanism[6] (see 1.2.1), including a cyclic 2',3'-phosphodiester as intermediate. The covalent structure of RNase T1 was determined by KENJI TAKAHASHI[81] 1971 (revised 1985[82]). The tertiary structure of the complex of RNase T1 with its inhibitor 2'-GMP was solved 1982 by UDO HEINEMANN and WOLFRAM SAENGER using x-ray structure analysis[31]. Further structure data acquired using x-ray structure analysis[3] or NMR spectroscopy[22,64] gave a deeper insight into the conformation and possible substrate binding sites of this enzyme.

Footnotes

...takadiastase^1.1

Takadiastase is a culture of Aspergillus oryzae on mois rice or wheat ban. It is used for the production of sake [2]