Bacterial ribosomal S1 proteins biodiversity
The obtained data make it possible to estimate the prevalence of groups
containing different numbers of structural S1 domains in the family of
the bacterial S1 proteins. Thus, one-, two-, three-, and five-domain S1
proteins account for 1%, 0.8%, 2% and 1.2% of all studied sequences,
respectively. Four- and six domain proteins are most represented: 33%
and 62%, respectively (Fig. 1a.). At the same time, as we showed above,
55% of all studied bacterial S1 sequences belong to the Proteobacteria,
16% and 17% belong to Firmicutes and Actinobacteria, respectively, and
6% to Bacteroidetes (Fig. 1b.).
Numerous studies showed that >88% of all bacterial
isolates belong to four phyla of bacteria (Big Four): Proteobacteria,
Firmicutes, Actinobacteria, and Bacteroidetes 33,34(Fig. 1c.). In fact, obtaining isolates that do not belong to the Big
Four is challenging, and therefore these four phyla dominate our current
understanding of microbiology 34. At the same time,
the number of microorganisms belonging to the Proteobacteria phyla was
highlighted in most studies determining the diversity of microorganisms,
with a range from 40 to 90%, either for isolation analysis or for
analysis of microbiomes 35–37. In general, the
dataset we study reflects the percentage of major bacterial phyla and
can be considered representative. The most representative groups are the
six-domain containing proteins S1 from Proteobacteria and Bacteroidetes
and the four-domain containing S1 proteins from Actinobacteria and
Firmicutes.