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A novel function of RNase P from Escherichia coli: processing of a suppressor tRNA precursor.
Author(s) -
Nomura T.,
Ishihama A.
Publication year - 1988
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1988.tb03230.x
Subject(s) - rnase p , terminator (solar) , biology , genetics , transfer rna , gene , escherichia coli , cleavage (geology) , operon , microbiology and biotechnology , rna , ionosphere , paleontology , physics , astronomy , fracture (geology)
The leuX gene of Escherichia coli codes for a suppressor tRNA and forms a single gene operon containing its own promoter and Q‐independent terminator. An analysis of the in vitro processing of leuX precursor revealed that the processing of the 5′ end took place in a single‐step reaction catalysed by RNase P while the 3′ processing involved two successive reactions. The endonucleolytic cleavage activity of the 3′ precursor sequence was found to copurify with RNase P. Heat inactivation of thermosensitive RNase P from two independent E. coli mutants abolished the cleavage activity of both the 5′ and 3′ ends. These results altogether suggest that RNase P carries the activity of 3′ end cleavage as well as that of 5′ processing. In the presence of Mg2+ alone, the leuX precursor was found to be self‐cleaved at a site approximately 13 nt inside from the 5′ end of mature tRNA. The self‐cleaved precursor tRNA was no longer processed by the 3′ endonuclease, suggesting that the 3′ endonuclease recognizes a specific conformation of the precursor tRNA for action.