Sequence homologies among E. coli ribosomal proteins: evidence for evolutionarily related groupings and internal duplications.

The complete or partial sequences of 47 E. coli ribosomal proteins described in the literature have been examined by computerized search and matching programs. In contrast to results previously reported by other investigators, sequence homologies were uncovered among some of these ribosomal proteins that are well beyond statistical expectations. Moreover, alignments of the most strongly homologous sequences suggested the existence of a network of family groupings. Several of these proteins also exhibit internal homologies, indicating that they have been elongated by a series of tandem duplications.