The nucleotide sequence of 16S rDNA from Euglenagracilis chloroplasts has been determined representing the first complete sequence of an algal chloroplast rRNA gene. The structural part of the 16S rRNA gene has 1491 nucleotides according to a comparative analysis of our sequencing results with the published 5′- and 3′-terminal “Tl-oligonucleotides” from 16S rRNA from E. gracilis. Alignment with 16S rDNA from Zeamays chloroplasts and E. coli reveals 80 and 72% sequence homology, respectively. Two deletions of 9 and 23 nucleotides are found which are identical in size and position with deletions observed in 16S rDNA of maize and tobacco chloroplasts and which seem to be characteristic for all chloroplast rRNA species. We also find insertions and deletions in E. gracilis not seen in 16S rDNA of higher plant chloroplasts. The 16S rRNA sequence of E. gracilis chloroplasts can be folded by base pairing according to the general 16S rRNA secondary structure model.

The nucleotide sequence of 16S rDNA from Euglena gracilis chloroplasts has been determined representing the first complete sequence of an algal chloroplast rRNA gene. The structural part of the 16S rRNA gene has 1491 nucleotides according to a comparative analysis of our sequencing results with the published 5'- and 3'-terminal "T1-oligonucleotides" from 16S rRNA from E. gracilis. Alignment with 16S rDNA from Zea mays chloroplasts and E. coli reveals 80 to 72% sequence homology, respectively. Two deletions of 9 and 23 nucleotides are found which are identical in size and position with deletions observed in 16S rDNA of maize and tobacco chloroplasts and which seem to be characteristic for all chloroplast rRNA species. We also find insertions and deletions in E. gracilis not seen in 16S rDNA of higher plant chloroplasts. The 16S rRNA sequence of E. gracilis chloroplasts can be folded by base pairing according to the general 16S rRNA secondary structure model.

In our hybrid-plasmid reconstruction analysis of lambda (lambdoid) DNA signal structures involved in phage DNA replication, we have detected a dual system alternatingly able to initiate a first primer-RNA synthesis. Both of them--the major, primase-dependent ori system and the minor and usually suppressed, RNA-polymerase-dependent oop system--act in conjunction with a common signal structure for inception of DNA synthesis. It appears that in situations such as this, where one has to deal with the existence of regular as well as backup systems serving the same function, straightforward conclusions are no longer possible in their genetic analysis. For example, even though the oop-DNA segment can be deleted entirely from bacteriophage lambda DNA without disturbing its ability to replicate, it may not be valid to conclude that the oop system has no function in DNA replication. Dual systems of this type or organization in general have also been observed previously for some other replicons such as the R-factors R6-5 and R6K (Timmis et al. 1978; Crosa et al., this volume) or the F factor (Helinski et al., this volume), and they may be more common than presently expected.

A nucleotide sequence comprising 960 base pairs of bacteriophage lambda DNA has been determined. The sequence includes the entire genes of the regulatory proteins cro and cII, and part of the O gene, together with control elements for their transcription and translation. The right-hand boundaries of the lambdaimm434 and lambdaimm21 substitutions and the cy42 mutation have been located.

A sequence of 50 residues in f1 DNA has been determined by the extension of a chemically synthesized octadeoxyribonucleotide by Escherichia coli DNA polymerase I, with radioactive nucleoside triphosphates and f1 DNA template. The polymerized product was synthesized either in the presence of manganese and a mixture of ribo- and deoxyribotriphosphates or in a magnesium-containing reaction with one or more of the four triphosphates absent. The sequence determination depended largely on fractionation of the polymerized products by two-dimensional "homochromatography." This approach and the techniques for the subsequent sequence analysis should be of general use for determining other sequences of DNA. Several features of this sequence suggest that it is located in an intercistronic region of f1 DNA.

FEBS LettersVolume 3, Issue 4 p. 253-256 Full-length articleFree Access Enzymatic hydrolysis of n-substituted met-tRNAM and met-tRNAF Y. Lapidot, Y. Lapidot Department of Biological Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel Institut für Genetik der Universität Freiburg, Freiburg, GermanySearch for more papers by this authorD. Inbar, D. Inbar Department of Biological Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel Institut für Genetik der Universität Freiburg, Freiburg, GermanySearch for more papers by this authorN. de Groot, N. de Groot Department of Biological Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel Institut für Genetik der Universität Freiburg, Freiburg, GermanySearch for more papers by this author Y. Lapidot, Y. Lapidot Department of Biological Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel Institut für Genetik der Universität Freiburg, Freiburg, GermanySearch for more papers by this authorD. Inbar, D. Inbar Department of Biological Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel Institut für Genetik der Universität Freiburg, Freiburg, GermanySearch for more papers by this authorN. de Groot, N. de Groot Department of Biological Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel Institut für Genetik der Universität Freiburg, Freiburg, GermanySearch for more papers by this author First published: June 01, 1969 https://doi.org/10.1016/0014-5793(69)80150-XCitations: 13AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat References 1 F. Cuzin, N. Kretchmer, R.E. Greenberg, R. Hurwitz, F. Chapeville, Proc. Natl. Acad. Sci. U.S., 58, (1967), 2079– CrossrefCASPubMedWeb of Science®Google Scholar 2 H. Kössel, U.L. RajBhandary, J. Mol. Biol., 35, (1968), 539– CrossrefCASPubMedWeb of Science®Google Scholar 3 Z. Vogel, A. Zamir, D. Elson, Proc. Natl. Acad. Sci. U.S., 61, (1968), 701– CrossrefCASPubMedWeb of Science®Google Scholar Z. Vogel, A. Zamir, D. Elson, Biochem. Biophys. Res. Commun., 33, (1968), 94– CrossrefCASPubMedWeb of Science®Google Scholar 4 N. de Groot, A. Panet, Y. Lapidot, Biochem. Biophys. Res. Commun., 31, (1968), 37– CrossrefCASPubMedWeb of Science®Google Scholar 5 N. de Groot, Y. Groner, and Y. Lapidot, Biochim. Biophys. Acta, in press. Google Scholar 6 D. Paulin, P. Yot, F. Chapeville, FEBS Letters, 1, (1968), 163– Wiley Online LibraryCASPubMedGoogle Scholar 7 H. Kössel, manuscript in preparation. Google Scholar 8 T. Seno, M. Kobayashi, S. Nishimura, Biochim. Biophys. Acta, 169, (1968), 80– CrossrefCASPubMedWeb of Science®Google Scholar 9 K.H. Muench, P. Berg, F.L. Cantoni D.R. Davies Progress in Nucleic Acid Research (1966), Harper and Row New York 375– Google Scholar 10 Y. Lapidot, N. de Groot, I. Fry-Shafrir, Biochim. Biophys. Acta, 145, (1967), 292– CrossrefCASPubMedWeb of Science®Google Scholar 11 Y. Lapidot, N. de Groot, S. Rappoport, Biochim. Biophys. Acta, 182, (1969), 105– CrossrefCASPubMedWeb of Science®Google Scholar 12 R.M. Hoskinson, H.G. Khorana, J. Biol. Chem., 240, (1965), 2129– CASPubMedWeb of Science®Google Scholar Citing Literature Volume3, Issue4June 01, 1969Pages 253-256 ReferencesRelatedInformation