One member of this family, from Bidobacterium longicum, UniProtKB:E8MGH8, has been characterised as an unusual beta-L-arabinofuranosidase enzyme, EC:3.2.1.185. It rleases l-arabinose from the l-arabinofuranose (Araf)-beta1,2-Araf disaccharide and also transglycosylates 1-alkanols with retention of the anomeric configuration. Terminal beta-l-arabinofuranosyl residues have been found in arabinogalactan proteins from a number of different plant species. beta-l-Arabinofuranosyl linkages with 1-4 arabinofuranosides are also found in the sugar chains of extensin and solanaceous lectins, hydroxyproline (Hyp)2-rich glycoproteins that are widely observed in plant cell wall fractions. The critical residue for catalytic activity is Glu-338, in a ET/SCAS sequence context [1].

1: Characterization of a novel beta-L-arabinofuranosidase in Bifidobacterium longum: functional elucidation of a DUF1680 protein family member. Fujita K, Takashi Y, Obuchi E, Kitahara K, Suganuma T; J Biol Chem. 2014;289:5240-5249. PMID:24385433