This family of proteins represents the family 31 carbohydrate-binding module of beta-1,2-xylanase. This protein is from Alcaligenes sp. strain XY-234. The AlcCBM31 module makes a beta-sandwich structure with an immunoglobulin fold and contains two intra-molecular disulfide bonds. AlcCBM31 shows affinity with only beta-1,3-xylan [1].

1: The first crystal structure of a family 31 carbohydrate-binding module with affinity to beta-1,3-xylan. Hashimoto H, Tamai Y, Okazaki F, Tamaru Y, Shimizu T, Araki T, Sato M; FEBS Lett. 2005;579:4324-4328. PMID:16061225