Figure 1. Ribosomal Cluster Genome Organization

This figure graphically illustrates the gene order and size for the coding sequences that comprise the S10, spc, and alpha operons. Each coding sequence is represented by a color bar that is proportional in size to the size of the coding regions. Comparisons between organisms are shown as vertical lines connecting the starting positions of each coding sequence. Gene insertions/deletions/and size variations can be discerned by comparing the bar for each organism to that of any other organism.

Gene order is exactly maintained for the four mycoplasma species, while gene order is similar for Ec and Hi with the exception of the presence of two additional genes (L30 and S4) for both organisms, and a third gene (HI0787) for Hi. In addition, Ec and Hi do not have adk, map, and infA located between secY and L36.

Bs is seen to possess characteristics that lie between Hi/Ec and the mycoplasma species. It contains L30, similar to Ec and Hi, but is missing S4 in the alpha operon, similar to Mc, Mg, Mp, and Uu. It also contains the three gene insertion of adk, map, and infA similar to the mycoplasma species.

With a few exceptions, gene size is similar for all of these organisms (see table 2). The size of this cluster for Mg is very similar to that of Uu and Mp, and with the exception of the open reading frame insertion/deletions, it is similar to that of all the other organisms.

Table 2. The Ribosomal Gene Cluster

This table provides an overview of the organization of the ribosomal protein gene cluster, along with providing a summary of some of the data compiled for this analysis. The three regulatory operons are indicated along with the gene and protein complement that make up each of these operons. For each organism the length of the intergenic region (Ig) between the stop codon of the indicated gene, and the start codon of the downstream gene is indicated. The length of the individual coding sequences are also indicated.

An Ig length of 1 indicates that no bases are shared between the stop and start codons. An Ig length of 0 indicates that the terminal A of the stop codon is shared with the initial A of the start codon.

HI0787 is a predicted ORF in Hi that is not present in any of the other organisms. Mg and Mp (and probably Uu and Mc) do not code for an L30 ribosomal protein. Ribosomal protein S4 is located elsewhere in the genome for the mycoplasma species, as well as for Bs. The three genes Adenylate kinase, Methionine amino peptidase, and Initiation factor 1 that are located between secY and L36 are present elsewhere in the genome for Ec and Hi. Following adk, no contiguous sequence information is available for Mc.