Mining metagenomic data for novel domains: BACON, a new carbohydrate-binding module

Third-generation sequencing has given new impetus to protein sequence database growth, revealing new domains. Description and analysis of these is required to further improve the coverage and utility of domain databases. A novel domain, here named BACON, was discovered from analysis of metagenomic data obtained from gut bacteria. Domain architectures unambiguously link its function to carbohydrate metabolism but a further strong connection to protease domains suggests that many BACON domains bind glycoproteins. Conserved residues in the BACON domain are also characteristic of carbohydrate binding while its biased phyletic distribution and other data suggest mucin as a potential specific target.