Physical-Chemical Properties of L-asparaginase Mutants From Rhodospirillum Rubrum which Showed Antitelomerase Activity

Abstract

Rru_A3730 protein is a bacterial Rhodospirillum rubrum L-asparaginase (RrA), which is known by its anticancer activity. RrA variants with point amino acid substitutions in the region of 150 amino acids residues: RrA17N, K149E, RrAE149R, V150P, F151T, RrА17N, E149R, V150P, RrAE149R, V150P, showed antiproliferative properties, and also by their ability to suppress telomerase activity. This work is devoted to comparison of physical-chemical and catalytic properties of these mutant forms of RrA. It is shown that pH optimum is in the alkaline zone (8.5 – 9.3); L-glutaminase and D-asparaginase activity is respectively not more than 0.1% and 1.6% of L-asparaginase for all studied variants of RrA. The presence of the N17-terminal amino acid sequence MASMTGGQMGRGSSRQ of the capsid protein of bacteriophage T7 in the RrA structure leads to an increase in the thermal stability of mutant RrA analogues (from 50°C to 56°C) and their resistance to denaturation in the presence of 3 – 4 M urea. It is of Metal ions exhibit multidirectional effects on L-asparaginase activity of RrA. K+, Ca2+, Zn2+, Cs+, Co2+ in significantly affect the activity of L-asparaginase, while Mn2+, Cu2+, Fe3+ ions inhibit it. There was no correlation between antitelomerase (antiproliferative) activity and kinetic properties of mutant forms of L-asparaginase RrA.

A Novel L-Asparaginase from Hyperthermophilic Archaeon Thermococcus sibiricus: Heterologous Expression and Characterization for Biotechnology Application

“…AAP92666.3) [ 55 , 56 ] and Rhodospirillum rubrum (GenBank accession No. QXG80441.1) [ 57 , 58 , 59 ] is about 27% and 33%, respectively. The identity between TsA and L-ASNases, FDA-approved for use as antileukemic agents, from E. coli (UniProtKB accession number P00805, marketed under the brand name Elspar, GenBank accession No.…”

“…Reduced L-ASNase activity was observed only in the presence of Fe 3+ . In previous data, inhibition of the enzyme activity by addition of Fe 3+ was reported for L-ASNase from mesophilic Erwinia carotovora [ 73 ] and mutant forms of Rhodospirillum rubrum L-ASNase [ 58 ].…”

Highly Active Thermophilic L-Asparaginase from Melioribacter roseus Represents a Novel Large Group of Type II Bacterial L-Asparaginases from Chlorobi-Ignavibacteriae-Bacteroidetes Clade

“…AAP92666.3) [32,33] and Rhodospirillum rubrum (GenBank accession No. QXG80441.1) [34][35][36] is about 32.7% and 41.7%, respectively. The identity between MrAII and FDA-approved L-ASNases from E. coli (UniProtKB accession number P00805, marketed under the brand name Elspar, GenBank accession No.…”