Preparation of Plasmid，M13 Phage，and Oligonucleoti...
The plasmid，M13 phage，and oligonucleotide probes for various photosynthetic genes of R.capsulatus are listed in Table 1 and Figure 1.M13 phage DNA was extracted according to the procedure described in the 1982 Bethesda Research Laboratories Cloning and Dideoxy Sequencing Instruction Manual.The nucleotide sequences of inserts in individual recombinant M13 phages were determined and confirmed by dideoxy sequencing［22］.Two oligodeoxynucleotides containing 15 bases complementary to the sequence encoding theβ subunit of LH-Ⅱ and to the open reading frame（ORF）C2397（see Figure 1 and Table 1）were synthesized on a Biosearch Sam One DNA synthesizer using phosphite triester chemistry and were purified by thin-layer chromatography［23］.
Table 1 M13 phage，plasmids，or oligonucleotides used as probes
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*Numbers（bp）correspond to positions shown in Figure 1.
tSingle-stranded probes synthesized from M13 DNA were complementary to known ORFs，based on DNA sequence analysis.
tNitrogenase reductase.(https://www.daowen.com)
Figure 1 Photosynthetic gene cluster organization and location of hybridization probes.BamHI and EcoRI restriction sites are shown within the 46-kb photosynthetic gene cluster from R.capsulatus carried by the R'plasmid pRPS404［10，15］.The BamHI-F and BamHI-C-EcoRI-B fragments are magnified and shown at top and bottom.The BamHI-E and-D fragments，containing the genes for Bchl biosynthetic enzymes，and the Bam HI-J，-H，-G，and-M fragments，containing the genes for Crt biosynthetic enzymes，are represented above pRPS404.Solid arrows indicate the coding regions and the direction of transcription.Open arrows represent putative protein-coding sequences（ORFs）.The small bars above or below these arrows indicate the hybridization probes for specific genes（see Table 1）
