Molecular mechanism of substrate recognition and specificity of tRNAHis guanylyltransferase during nucleotide addition in the 3'-5' direction.
RNA
; 24(11): 1583-1593, 2018 11.
Article
in En
| MEDLINE
| ID: mdl-30111535
ABSTRACT
The tRNAHis guanylyltransferase (Thg1) transfers a guanosine triphosphate (GTP) in the 3'-5' direction onto the 5'-terminal of tRNAHis, opposite adenosine at position 73 (A73). The guanosine at the -1 position (G-1) serves as an identity element for histidyl-tRNA synthetase. To investigate the mechanism of recognition for the insertion of GTP opposite A73, first we constructed a two-stranded tRNAHis molecule composed of a primer and a template strand through division at the D-loop. Next, we evaluated the structural requirements of the incoming GTP from the incorporation efficiencies of GTP analogs into the two-piece tRNAHis Nitrogen at position 7 and the 6-keto oxygen of the guanine base were important for G-1 addition; however, interestingly, the 2-amino group was found not to be essential from the highest incorporation efficiency of inosine triphosphate. Furthermore, substitution of the conserved A73 in tRNAHis revealed that the G-1 addition reaction was more efficient onto the template containing the opposite A73 than onto the template with cytidine (C73) or other bases forming canonical Watson-Crick base-pairing. Some interaction might occur between incoming GTP and A73, which plays a role in the prevention of continuous templated 3'-5' polymerization. This study provides important insights into the mechanism of accurate tRNAHis maturation.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
RNA, Transfer, His
/
Nucleotidyltransferases
Limits:
Humans
Language:
En
Journal:
RNA
Journal subject:
BIOLOGIA MOLECULAR
Year:
2018
Document type:
Article
Affiliation country:
Japan