Koji Ohnishi

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Published sequence data of MHC genes, cDNAs and MHC products were analyzed for their sequence homologies. Alignment statistics revealed that class I gene products consist of four mutually homologous domains, and that class II beta gene products is composed of three mutually homologous domains. Not only extracellular domains but also newly discovered(More)
Internal homology units of F1-ATPase epsilon and gamma subunits were searched by computer-aided methods. The epsilon in E. coli (EC) and maize chloroplast (Ch1) was found to consist of three homologous domains, named domains I, II and III (amino acids 1-47, 48-95 and 96-139 for EC). The gamma in E. coli was demonstrated to have at least six homologous(More)
The origin and early evolution of genetic codon system and early mRNAs were analyzed from a viewpoint of primordial gene theory and the poly-tRNA theory. A hypothetical 25-amino acid (aa)-primordial peptide was deduced from internal aa-sequence homology of adenylate kinases. Theoretical models were made which can reasonably explain how primitive tRNA(s)(More)
Poly-tRNA theory have revealed that the tRNA gene-clusters in the Bacillus subtilis trrnD- and rrnB-operons are relics of early peptide-synthesizing RNA apparatus. The trrnD-type and rrnB-type poly-tRNA models were re-analyzed by using recent databases. The results elucidated that the 16 amino acid (aa)-trrnD- and the 21 aa-rrnB-peptides (whose aa sequences(More)
tRNA was found to have emerged by tandem duplication of a ca. 37-base RNA ("semi-tRNA"). The most ancestral anticodon was "(5')CCA(3')". The peptidyltransferase (PT) region of 23S rRNA was concluded to be a 5S rRNA homologue. Important evidences were obtained for elucidating that the RNA transcript from the Bacillus subtilis (BSU) trrnD operon is a relic of(More)
The 330 residue-long N-terminal domains (NTDs) of beta and beta' subunits of the Escherichia coli RNA polymerase (RPase) core enzyme were found to be significantly homologous to the entire length of its alpha subunit. The C-terminal domains (CTDs) of the RPase beta subunit and DNA primase (dnaG protein) were not only strongly homologous to each other but(More)
Alignment of the amino acid (aa) sequences of T7 phage DNA polymerase (DPase), E. coli DNA polymerase I (Pol I) and MS2 phage RNA replicase beta subunit (MS2 Repl) were established by computer-aided methods. The results showed that the entire length (aa's 16-704) of T7 DPase is homologous to Pol I aa's 207-928(C-term) with 21.5% aa identity, and that(More)
The bases 1175-1542 (3'-term.) and 94-510 of the E. coli (EC) 16S rRNA are both homologous to the [5S rRNA-tRNA Asn-tRNA(Ser)-tRNA(Glu)-tRNA(Val)-tRNA(Met)] region of the Bacillus subtilis (BSU) trrnD operon, and to the S12 and S7 r-protein-encoding region (S12/S7 region) in the EC str operon. The 2570-2906 (3'-term.) of the EC 23S rRNA is also homologous(More)