Disease relevance of ECs2513

• Similarly, RNase D action on the E. coli tRNATyr precursor is limited, whereas RNase II causes extensive degradation [1].
• Moreover, three recombinant HIV-1 RT preparations expressed and purified in different laboratories by various procedures exhibit RNase D activity [2].
• We refer to this unusual activity as RNase D. Two lines of evidence indicate that the specific RNase D activity is an integral part of recombinant HIV RT [2].
• The implications of these findings for the role of RNase D in bacterial and bacteriophage tRNA metabolism, and the possible involvement of alternative enzymes, are discussed [3].

High impact information on ECs2513

• Alteration of two to five uridine residues within this sequence has no effect on mRNA levels but decreases RNase D protein and activity by as much as 95%, indicating that the U-rich sequence acts as an enhancer of translation [4].
• A new ribonuclease, RNase BN, has been identified and partially purified from a strain of Escherichia coli lacking RNase II and RNase D by using the artificial tRNA precursor tRNA-C-[14C]U as substrate [5].
• In contrast to the processive mode of hydrolysis by RNase II, RNase D removes nucleotides randomly and slows down greatly at the -C-C-A sequence, thereby allowing the tRNA to be aminoacylated and protected from further degradation [1].
• This alteration led to an 11-fold elevation of RNase D expression in single-copy plasmids [6].
• However, since mutant Escherichia coli strains devoid of RNase D display a normal phenotype, it has not been possible to ascertain the enzyme's function or even to determine which RNA is its substrate in vivo [7].

Biological context of ECs2513

• Escherichia coli RNase D. Catalytic properties and substrate specificity [8].
• We have determined the nucleotide sequence of a 1.4-kb-pair fragment of the E. coli chromosome that carries the complete rnd gene encoding RNase D, a putative tRNA processing enzyme [9].
• Besides the catalytic domain, RNase D also contains two structurally similar alpha-helical domains with no discernible sequence homology between them [10].

Associations of ECs2513 with chemical compounds

• A variety of RNAs were tested as substrates for RNase D. Alteration of the 3'-terminal base has no effect on the rate of hydrolysis, whereas modification of the 3'-terminal sugar has a major effect. tRNA terminating with a 3'-phosphate is completely inactive as a substrate [8].

Other interactions of ECs2513

• Studies of the mode of action of RNase D indicate that it is an exonuclease which initiates hydrolysis at the 3'-terminus and removes 5'-mononucleotides in a random fashion [8].

Analytical, diagnostic and therapeutic context of ECs2513

• Surprisingly, deletion of the hairpin structure elevates rnd mRNA levels only slightly (less than 2-fold), but it dramatically decreases RNase D expression (greater than 95%), measured both by activity and immunoblotting [6].

References