PMID:9214656
| Citation |
Motorin, Y, Bec, G, Tewari, R and Grosjean, H (1997) Transfer RNA recognition by the Escherichia coli delta2-isopentenyl-pyrophosphate:tRNA delta2-isopentenyl transferase: dependence on the anticodon arm structure. RNA 3:721-33 |
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| Abstract |
To elucidate the sequence elements required in the anticodon stem for the recognition of Escherichia coli tRNA(Ser) (GGA) by the E. coli isopentenyl-tRNA:A37 transferase (IPTT), which result in the conversion of A37 into isopentenylated i6A37, we have tested and characterized in vitro T7-runoff transcripts of 17 variants of E. coli tRNA(Ser)(GGA) and 7 other tRNAs from E. coli and yeast. Our results indicate that, instead of a stringent specific anticodon stem and loop sequence, the key feature required for the recognition of E. coli tRNAs by IPTT is the A36A37A38 sequence occurring within the seven-membered anticodon loop, and the retention of the standard helical structure and flexibility, especially in the proximal anticodon stem. The G30*U40 mismatch base pair close to the anticodon loop is strictly avoided. The frequent occurrence of a C-G base pair in the three stem locations closest to the loop (positions 29-41, 30-40 and 31-39) or the occurrence of even one such C-G base pair along with some other similarly less suited, but individually tolerated deviations can also totally abolish the A37 isopentenylation of tRNA. For the position 30-40, the G-C base pair is shown uniquely suited, whereas for the adjoining 29-41 stem location, a purine-pyrimidine base pair with pyrimidine on the 3'-side is strongly preferred. Retention of the overall 3D tRNA structure is favorable for isopentenylation and allows some tolerance of proximal stem sequence deviations. Our data suggest a recognition mode that implies the interaction of IPTT with the strictly conserved A36A37A38 sequence and the other functional groups located in the minor groove of the anticodon stem. |
| Links | |
| Keywords |
Alkyl and Aryl Transferases; Anticodon/chemistry; Anticodon/metabolism; Base Composition; Base Sequence; Conserved Sequence; Databases, Factual; Escherichia coli/enzymology; Escherichia coli/genetics; Isopentenyladenosine/metabolism; Molecular Sequence Data; Mutation; Nucleic Acid Conformation; RNA, Transfer/chemistry; RNA, Transfer/genetics; RNA, Transfer/metabolism; RNA, Transfer, Ser/chemistry; RNA, Transfer, Ser/genetics; RNA, Transfer, Ser/metabolism; Structure-Activity Relationship; Substrate Specificity; Transcription, Genetic; Transferases/metabolism |
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