In silico analysis of large microbial surface proteins.

We analyzed the longest predicted proteins encoded in complete microbial genomes. They could be separated into two main classes: non-ribosomal peptide synthetases involved in secondary metabolism and surface proteins, many of them with a predicted or experimentally observed role in bacterial adhesion and biofilm formation. Such proteins, generally showing a repetitive structure, are widespread among prokaryotes and can be grouped into several different families based on sequence alignment, characteristics and predicted motifs. This classification may help in the characterization of newly described adhesins. The results of this study indicate that cell-cell interactions and biofilm formation are common events in the microbial world and take place via similar molecular mechanisms.