Untitled

Abstract

The chloroplast chromosome of spinach (Spinacia oleracea) is a double-stranded circular DNA molecule of 150,725 nucleotide pairs. A comparison of this chromosome with those of the three other autotrophic dicotyledons for which complete DNA sequences of plastid chromosomes are available confirms a conserved overall structure. Three classes of open reading frames were distinguished: (1) genes of known function which include 108 unique loci, (2) three hypothetical chloroplast reading frames (ycfs) that are highly conserved interspecifically, and (3) species-specific or rapidly diverging 'open reading frames'. A detailed transcript study of one of the latter (ycf15) shows that these loci may be transcribed, but do not constitute protein-coding genes.

Structure of the Intermolecular Complex between Plastocyanin and Cytochrome f from Spinach

“…Determination and Refinement of the Model Structure of Spinach Cytochrome f-The sequence of spinach apocytochrome f precursor (53,54) was retrieved from the Swiss-Prot Data Base available at expasy. org/sprot/.…”

Bacterial Alarmone, Guanosine 5′‐Diphosphate 3′‐Diphosphate (ppGpp), Predominantly Binds the β′ Subunit of Plastid‐Encoded Plastid RNA Polymerase in Chloroplasts

“…[30] The completion of this reaction was monitored by HPLC analysis. To synthesize radioactive 6-thioppGpp, 6-thioGDP (7) was incubated in a reaction mixture containing [g- 32 P]ATP and a pyrophosphate transferase. After 2 h, this re-A C H T U N G T R E N N U N G action mixture was extracted by phenol/chloroform, and to remove traces of phenol, an equal volume of chloroform was added to the aqueous layer.…”

“…The complete nucleotide sequence of the plastid chromosome of A C H T U N G T R E N N U N G spinach has been reported. [32] Therefore, we selected spinach chloroplasts for RNAP preparation. Since purification of chloroplast RNAP from mature plant leaves is difficult due to the association of many proteins with chloroplast RNAP, [15] we used partially purified chloroplast RNAP (see the Experimental Section) to examine the inhibitory activities of 6-thioppGpp and ppGpp.…”

“…[30] An equivalent amount of [g- 32 P]ATP to 6-thioGDP was added to the reaction mixture. Accordingly, the radioactive nucleotide in the reaction mixture was almost solely radioactive 6-thioppGpp due to A C H T U N G T R E N N U N G effective enzymatic catalysis.…”

Two New Mexican Endemic Species of <I>Iresine</I> (Amaranthaceae)

“…Boundaries of the genomic regions studied were annotated using multiple sequence alignment in comparison with completely sequenced and annotated plastid ge nomes of Nicotiana tabacum (Z00044; Shinozaki & al. 1986) and Spinacia oleracea (AJ400848; Schmitz-Linneweber & al. 2001).…”