BNR repeat-like domain. This family of proteins contains BNR-like repeats suggesting these proteins may act as sialidases.

Predicted neuraminidase (sialidase) [Carbohydrate transport and metabolism, Cell wall/membrane/envelope biogenesis].

Non-viral sialidases. Sialidases or neuraminidases function to bind and hydrolyze terminal sialic acid residues from various glycoconjugates, they play vital roles in pathogenesis, bacterial nutrition and cellular interactions. They have a six-bladed, beta-propeller fold with the non-viral sialidases containing 2-5 Asp-box motifs (most commonly Ser/Thr-X-Asp-[X]-Gly-X-Thr- Trp/Phe). This CD includes eubacterial and eukaryotic sialidases.

Sortilin, neurotensin receptor 3,. Sortilin, also known in mammals as neurotensin receptor-3, is the archetypical member of a Vps10-domain (Vps10-D) that binds neurotrophic factors and neuropeptides. This domain constitutes the entire luminal part of Sortilin and is activated in the trans-Golgi network by enzymatic propeptide cleavage. The structure of the domain has been determined as a ten-bladed propeller, with up to 9 BNR or beta-hairpin turns in it. The mature receptor binds various ligands, including its own propeptide (Sort-pro), neurotensin, the pro-forms of nerve growth factor-beta (NGF)6 and brain-derived neurotrophic factor (BDNF)7, lipoprotein lipase (LpL), apo lipoprotein AV14 and the receptor-associated protein (RAP)1.

Glycosyl hydrolase family 43. This glycosyl hydrolase family 43 (GH43)-like subfamily includes uncharacterized enzymes similar to those with beta-1,4-xylosidase (xylan 1,4-beta-xylosidase; EC 3.2.1.37), beta-1,3-xylosidase (EC 3.2.1.-), alpha-L-arabinofuranosidase (EC 3.2.1.55), arabinanase (EC 3.2.1.99), xylanase (EC 3.2.1.8), endo-alpha-L-arabinanase and galactan 1,3-beta-galactosidase (EC 3.2.1.145) activities. These are inverting enzymes (i.e. they invert the stereochemistry of the anomeric carbon atom of the substrate) that have an aspartate as the catalytic general base, a glutamate as the catalytic general acid and another aspartate that is responsible for pKa modulation and orienting the catalytic acid. Many of the enzymes in this family display both alpha-L-arabinofuranosidase and beta-D-xylosidase activity using aryl-glycosides as substrates. A common structural feature of GH43 enzymes is a 5-bladed beta-propeller domain that contains the catalytic acid and catalytic base. A long V-shaped groove, partially enclosed at one end, forms a single extended substrate-binding surface across the face of the propeller.