Glycoside hydrolase family 130 consists of phosphorylases and hydrolases for beta-mannosides. Here, we characterized beta-1,2-mannobiose phosphorylase from Listeria innocua (Lin0857) and determined its crystal structures complexed with beta-1,2-linked mannooligosaccharides. beta-1,2-Mannotriose was bound in a U-shape, interacting with a phosphate analog at both ends. Lin0857 has a unique dimer structure connected by a loop, and a significant open-close loop displacement was observed for substrate entry. A long loop, which is exclusively present in Lin0857, covers the active site to limit the pocket size. A structural basis for substrate recognition and phosphorolysis was provided. (C) 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.