TY - JOUR
T1 - Nucleotides of tRNA (Glu) involved in recognition by barley chloroplast glutamyl-tRNA synthetase and glutamyl-tRNA reductase
AU - Willows, Robert D.
AU - Gamini Kannangara, C.
AU - Pontoppidan, Bo
PY - 1995/9/19
Y1 - 1995/9/19
N2 - The biosynthesis of δ-aminolevulinate (ALA), via the C-5 pathway, requires tRNA(Glu) as a cofactor for the glutamyl tRNA(Glu) synthetase and the glutamyl tRNA(Glu) reductase which are the first two enzymes in this three step pathway. These two enzymes form a ternary complex with the tRNA(Glu) inChlamydomonas reinhardtii suggesting that the recognition elements on the tRNA cofactor are different for each enzyme. Chemical modification and comparative studies with tRNA(Glu)s from a number of species were used to determine the nucleotides involved in the recognition of the barley chloroplast tRNA(Glu) by the barley enzymes. The barley chloroplast tRNA(Glu) is chemically modified both before and after ligation to glutamate with monobromobimane or CNBr. The chemically modified tRNA(Glu) is a poor substrate for the glutamyl-tRNA synthetase and the chemically modified glutamyl-tRNA(Glu) is used as a substrate for glutamyl-tRNA(Glu) reductase. The tRNA(Glu) from the chloroplasts of barley,Chlamydomonas reinhardtii, tobacco, cucumber, wheat and spinach and tRNA(Glu) fromSynechocystis PCC6803, Escherichia coli, barley germ and bakers yeast and the barley chloroplast tRNA(Gln) are all effective substrates for the barley chloroplast glutamyl-tRNA synthetase. A comparison of the sequences of these tRNAs shows 19 conserved bases and five of these bases, G10, A26, U34, U35 and A37 are suggested as recognition elements of barley glutamyl tRNA(Glu) synthetase by assuming a similar binding orientation as in the crystal structure of theE. coli tRNA(Gln) GlnRS complex. The glutamyl-tRNA(Glu) fromE. coli, bakers yeast and bakers germ and the barley chloroplast glutamyl-tRNA(Gln) are not effective substrates for the barley chloroplast glutamyl-tRNA(Glu) reductase. A comparison of the sequences of these four tRNA species with the sequences of the tRNA(Glu) species that can be used as substrate by the glutamyl-tRNA(Glu) reductase yields seven common differences in the primary sequence. These 7 nucleotides, A7-U66, U29-A41, A53-U61, and U72 are expected to be required for recognition by the barley chloroplast glutamyl-tRNA(Glu) reductase.
AB - The biosynthesis of δ-aminolevulinate (ALA), via the C-5 pathway, requires tRNA(Glu) as a cofactor for the glutamyl tRNA(Glu) synthetase and the glutamyl tRNA(Glu) reductase which are the first two enzymes in this three step pathway. These two enzymes form a ternary complex with the tRNA(Glu) inChlamydomonas reinhardtii suggesting that the recognition elements on the tRNA cofactor are different for each enzyme. Chemical modification and comparative studies with tRNA(Glu)s from a number of species were used to determine the nucleotides involved in the recognition of the barley chloroplast tRNA(Glu) by the barley enzymes. The barley chloroplast tRNA(Glu) is chemically modified both before and after ligation to glutamate with monobromobimane or CNBr. The chemically modified tRNA(Glu) is a poor substrate for the glutamyl-tRNA synthetase and the chemically modified glutamyl-tRNA(Glu) is used as a substrate for glutamyl-tRNA(Glu) reductase. The tRNA(Glu) from the chloroplasts of barley,Chlamydomonas reinhardtii, tobacco, cucumber, wheat and spinach and tRNA(Glu) fromSynechocystis PCC6803, Escherichia coli, barley germ and bakers yeast and the barley chloroplast tRNA(Gln) are all effective substrates for the barley chloroplast glutamyl-tRNA synthetase. A comparison of the sequences of these tRNAs shows 19 conserved bases and five of these bases, G10, A26, U34, U35 and A37 are suggested as recognition elements of barley glutamyl tRNA(Glu) synthetase by assuming a similar binding orientation as in the crystal structure of theE. coli tRNA(Gln) GlnRS complex. The glutamyl-tRNA(Glu) fromE. coli, bakers yeast and bakers germ and the barley chloroplast glutamyl-tRNA(Gln) are not effective substrates for the barley chloroplast glutamyl-tRNA(Glu) reductase. A comparison of the sequences of these four tRNA species with the sequences of the tRNA(Glu) species that can be used as substrate by the glutamyl-tRNA(Glu) reductase yields seven common differences in the primary sequence. These 7 nucleotides, A7-U66, U29-A41, A53-U61, and U72 are expected to be required for recognition by the barley chloroplast glutamyl-tRNA(Glu) reductase.
KW - (Barley)
KW - Aminolevulinic acid
KW - Chlorophyll biosynthesis
KW - Glutamate
KW - Glutamyl tRNA reductase
KW - Glutamyl tRNA synthetase
KW - tRNA identity
UR - http://www.scopus.com/inward/record.url?scp=0029021234&partnerID=8YFLogxK
U2 - 10.1016/0167-4781(95)00105-P
DO - 10.1016/0167-4781(95)00105-P
M3 - Article
C2 - 7548209
AN - SCOPUS:0029021234
VL - 1263
SP - 228
EP - 234
JO - BBA - Gene Structure and Expression
JF - BBA - Gene Structure and Expression
SN - 0167-4781
IS - 3
ER -