title: Crystal structure of a key enzyme in the agarolytic pathway, α-neoagarobiose hydrolase from Saccharophagus degradans 2-40.
abstract: In agarolytic microorganisms, α-neoagarobiose hydrolase (NABH) is an essential enzyme to metabolize agar because it converts α-neoagarobiose (O-3,6-anhydro-alpha-l-galactopyranosyl-(1,3)-d-galactose) into fermentable monosaccharides (d-galactose and 3,6-anhydro-l-galactose) in the agarolytic pathway. NABH can be divided into two biological classes by its cellular location. Here, we describe a structure and function of cytosolic NABH from Saccharophagus degradans 2-40 in a native protein and d-galactose complex determined at 2.0 and 1.55 Å, respectively. The overall fold is organized in an N-terminal helical extension and a C-terminal five-bladed β-propeller catalytic domain. The structure of the enzyme-ligand (d-galactose) complex predicts a +1 subsite in the substrate binding pocket. The structural features may provide insights for the evolution and classification of NABH in agarolytic pathways.
authors.affiliation: Physical Bioscience Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Sung Chul
authors.initials: SC
authors.lastname: Ha
authors.forename: Saeyoung
authors.initials: S
authors.lastname: Lee
authors.forename: Jonas
authors.initials: J
authors.lastname: Lee
authors.forename: Hee Taek
authors.initials: HT
authors.lastname: Kim
authors.forename: Hyeok-Jin
authors.initials: HJ
authors.lastname: Ko
authors.forename: Kyoung Heon
authors.initials: KH
authors.lastname: Kim
authors.forename: In-Geol
authors.initials: IG
authors.lastname: Choi
mesh_terms: D000362:Agar / Q000737:chemistry / Q000378:metabolism; D034241:Alteromonadaceae / Q000201:enzymology*; D003001:Cloning, Molecular; D003600:Cytosol / Q000201:enzymology; D004186:Disaccharidases / Q000737:chemistry* / Q000235:genetics; D011487:Protein Conformation
chemical_list: D000362:Agar; D004186:Disaccharidases; C039308:neoagarobiose hydrolase