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Related domains in yeast tRNA ligase, bacteriophage T4 polynucleotide kinase and RNA ligase, and mammalian myelin 2',3/‐cyclic nucleotide phosphohydrolase revealed by amino acid squence comparison
Author(s) -
Koonin Eugene V.,
Gorbalenya Alexander E.
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)81015-g
Subject(s) - rna ligase , biochemistry , biology , dna ligase , transfer rna , microbiology and biotechnology , rna , enzyme , gene
Related domains containing the purine NTP‐binding sequence pattern have been revealed in two enzymes involved in tRNA processing, yeast tRNA ligase and phage T4 polynucleotide kinase, and in one of the major proteins of mammalian nerve myelin sheath, 2',3'‐cyclic nucleotide 3'‐phospho‐hydrolase (CNPase). It is suggested that, similarly to the tRNA processing enzymes, CNPase possesses polynucleotide kinase activity, in addition to the phosphohydrolase one. It is speculated that CNPase may be an authentic mammalian polynucleotide kinase recruited as a structural component of the myelin sheath, analogously to the eye lens crystallins. Significant sequence similarity was revealed also between the N‐terminal regions of yeast tRNA ligase and phage T4 RNA ligase. A tentative scheme of the domainal organizations for the three complex enzymes is proposed. According to this model, tRNA ligase contains at least three functional domains, in the order: N‐ligase‐kinase‐phosphohydrolase‐C, whereas poly‐nucleotide kinase and CNPase encompass only the two C‐terminal domains in the same order.