Genetic Determinants of Xylan Utilization in Humisphaera borealis M1803T, a Planctomycete of the Class Phycisphaerae

Abstract — Planctomycetes of the class Phycisphaerae are aerobic and anaerobic heterotrophic bacteria that colonize a wide range marine terrestrial habitats. Their functional roles in environment, however, still poorly understood. Humisphaera borealis M1803 T is one very few characterized planctomycetes this class. It also first described representative previously uncultured group WD2101, which commonly detected soils peatlands. This work analyzed genetic determinants define ability to grow on xylan, plant cell wall polymers. The whole genome sequence analysis planctomycete resulted identification five genes encoding proteins homologous endo-β-xylanases. For two these proteins, evolutionarily closer experimentally homologs with other substrate specificities were found. In member GH10 family glycoside hydrolases, active center enzyme was destroyed. We consider from GH62 GH141 families as most likely candidates for role β-xylanase responsible xylan utilization. Phylogenetic GH10, GH62, carried out. lateral transfers evolution hydrolases their close discussed.