Molecular and cellular studies of tryptophanyl-tRNA synthetase using monoclonal antibodies. Evaluation of a common antigenic determinant in eukaryotic, prokaryotic and archaebacterial enzymes which maps outside the catalytic domain.
Monoclonal antibodies referred to as Am1, Am2 and Am3 against highly purified bovine tryptophanyl-tRNA synthetase were prepared. Am2 antibodies inhibit the Trp-tRNA synthetase activity and interact with the active truncated enzyme forms (dimers of either 40-kDa or 51-kDa fragments) produced by limited proteolysis. Am1 and Am3 antibodies exert no effect on the Trp-tRNA synthetase activity; epitopes recognized by them are mapped close to one another and reside at the dispensable part of the Trp-tRNA synthetase molecule. Am1 cross-reacts with Trp-tRNA synthetases of eukaryotic, prokaryotic and archaebacterial species, as revealed by immunoblot analysis. A rapid two-step technique was developed for isolating electrophoretically homogeneous Trp-tRNA synthetase from Escherichia coli. The purified enzyme interacted with Am1, but not with Am2 and Am3 antibodies taken at the same concentrations. As in the case of eukaryotic Trp-tRNA synthetase, Am1 did not influence the activity of Trp-tRNA synthetase from E. coli. From the aforementioned results it follows that: (a) the conservation of part of the Trp-tRNA synthetase structure which is not directly involved in the formation of the catalytic centre of prokaryotic and eukaryotic Trp-tRNA synthetases suggests that the dispensable part of the molecule might be involved in some additional biological function(s) of Trp-tRNA synthetase besides tRNA(Trp) charging; (b) the common antigenic determinant in Trp-tRNA synthetase of eukaryotes, prokaryotes and archaebacteria indicates that this enzyme was presumably present in the common ancestor of the above organisms.
Beresten
S F
SF
Engelhardt Institute of Molecular Biology, USSR Academy of Sciences, Moscow.
Zargarova
T A
TA
Favorova
O O
OO
Rubikaite
B I
BI
Ryazanov
A G
AG
Kisselev
L L
LL
D000604:Amino Acyl-tRNA Synthetases / Q000276:immunology*; D000818:Animals; D000911:Antibodies, Monoclonal; D001105:Archaea / Q000201:enzymology*; D001419:Bacteria / Q000201:enzymology*; D005075:Biological Evolution; D002417:Cattle; D000939:Epitopes / Q000032:analysis*; D004926:Escherichia coli / Q000201:enzymology; D051379:Mice; D008807:Mice, Inbred BALB C; D010449:Peptide Mapping; D014369:Tryptophan-tRNA Ligase / Q000032:analysis / Q000276:immunology* / Q000302:isolation & purification
D000911:Antibodies, Monoclonal; D000939:Epitopes; D000604:Amino Acyl-tRNA Synthetases; D014369:Tryptophan-tRNA Ligase