title: Asp141 and the Hydrogen-Bond Chain Asp141-Asn109-Asp33 Are Respectively Essential for GT80 Sialyltransferase Activity and Structural Stability.
abstract: Sialyltransferases are key enzymes involved in the biosynthesis of biologically and pathologically important sialic acid-containing molecules in nature. In this study, the activity of a putative sialyltransferase (Pm0160) harboring an inherent mutation D141Y in the conserved DDG motif, which has been identified in GT52 and GT80 families, was restored by reverse mutation. More interestingly, a hydrogen-bond chain was found to form between three conserved residues (Asp141, Asn109, and Asp33) of GT80 sialyltransferases based on recently determined crystal structures. Our mutagenesis experiments demonstrated that the hydrogen-bond chain connecting the general base Asp141 with Nβ4, Nβ1, and Nα1 plays an essential role in maintaining protein structural stability other than keeping the general base Asp141 in a productive orientation for sialic acid transfer.
authors.affiliation: College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Shandong, 271018, China. caiyum@163.com.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Chen
authors.forename: Yuanming
authors.initials: Y
authors.lastname: Wang
authors.forename: Zhenping
authors.initials: Z
authors.lastname: Ma
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.forename: Weiqing
authors.initials: W
authors.lastname: Han
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.forename: Yumei
authors.initials: Y
authors.lastname: Cai
authors.forename: Jiansong
authors.initials: J
authors.lastname: Cheng
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012799:Sialyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: D012799:Sialyltransferases; C029156:N-acetyllactosaminide alpha-2,3-sialyltransferase