Inosine-uridine Nucleoside N-ribohydrolase; Chain A
inosine-uridine preferring nucleoside hydrolase
ASP 10;ASP 15;THR 126;ASP 241(Ca2+ binding)
ASP 10;ASP 15;THR 126;ASP 242(Ca2+ binding)
Binding modes for substrate and a proposed transition-state analogue of protozoan nucleoside hydrolase.
Inosine-uridine nucleoside hydrolase from Crithidia fasciculata. Genetic characterization, crystallization, and identification of histidine 241 as a catalytic site residue.
Three-dimensional structure of the inosine-uridine nucleoside N-ribohydrolase from Crithidia fasciculata.
Purine-specific nucleoside N-ribohydrolase from Trypanosoma brucei brucei. Purification, specificity, and kinetic mechanism.
Isozyme-specific transition state inhibitors for the trypanosomal nucleoside hydrolases.
Trypanosomal nucleoside hydrolase. A novel mechanism from the structure with a transition-state inhibitor.
Nucleoside hydrolase from Leishmania major. Cloning, expression, catalytic properties, transition state inhibitors, and the 2.5-a crystal structure.
Purification, characterization, and gene cloning of purine nucleosidase from Ochrobactrum anthropi.
Structure and function of a novel purine specific nucleoside hydrolase from Trypanosoma vivax.
Enzyme-substrate interactions in the purine-specific nucleoside hydrolase from Trypanosoma vivax.
Computer simulations of trypanosomal nucleoside hydrolase: determination of the protonation state of the bound transition-state analogue.
Exploring nucleoside hydrolase catalysis in silico: molecular dynamics study of enzyme-bound substrate and transition state.
This enzyme belongs to the IU-nuceloside hydrolase family. This enzyme is homologous to ribosylpyrimidine nucleosidase (EC 3.2.2.8; S00751 in EzCatDB). According to the literature [2] & [4], The oxocarbonium ion is formed in the transition state, which is characterstic of an SN1-like catalytic mechanism. The paper [3] on crystal structure suggested that His241 can act as proton donor for the leaving nitrogenous base, whilst the paper [5] mentioned that His82 as well as His241 can protonates the leaving group. Asp14 is reported to have a hydrogen-bonding interaction with His241 [3]. Moreover, the papers [5], [6] and [7] suggested that metal or Ca2+ -bound water can attack the C1' atom after the oxocarbonium ion has been formed. One of the aspartic acid residues, Asp10, Asp15, Thr126 and Asp242, is proposed to be the group which will act as a general base, extracting the proton from the incoming water nucleophile, according to the paper [3]. The paper [12] based on molecular simulation suggested that the proton will be transferred from the activated water through Asp10 to Asp15 to water pool.