title: Alteration of the quaternary structure of human UDP-glucose dehydrogenase by a double mutation.
abstract: There are conflicting views for the polymerization process of human UDP-glucose dehydrogenase (UGDH) and no clear evidence has been reported yet. Based on crystal coordinates for Streptococcus pyogenes UGDH, we made double mutant A222Q/S233G. The double mutagenesis had no effects on expression, stability, and secondary structure. Interestingly, A222Q/S233G was a dimeric form and showed an UGDH activity, although it showed increased Km values for substrates. These results suggest that Ala222 and Ser233 play an important role in maintaining the hexameric structure and the reduced binding affinities for substrates are attributable to its altered subunit communication although quaternary structure may not be critical for catalysis.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul 138-736, Korea.
authors.forename: Jae-Wan
authors.initials: JW
authors.lastname: Huh
authors.forename: Seung-Ju
authors.initials: SJ
authors.lastname: Yang
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Hwang
authors.forename: Myung-Min
authors.initials: MM
authors.lastname: Choi
authors.forename: Hyun-Ju
authors.initials: HJ
authors.lastname: Lee
authors.forename: Eun-A
authors.initials: EA
authors.lastname: Kim
authors.forename: Soo Young
authors.initials: SY
authors.lastname: Choi
authors.forename: Jene
authors.initials: J
authors.lastname: Choi
authors.forename: Hea-Nam
authors.initials: HN
authors.lastname: Hong
authors.forename: Sung-Woo
authors.initials: SW
authors.lastname: Cho
mesh_terms: D000409:Alanine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019943:Amino Acid Substitution; D001665:Binding Sites / Q000235:genetics; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007700:Kinetics; D009154:Mutation; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D012694:Serine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D014533:Uridine Diphosphate Glucose Dehydrogenase / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism
chemical_list: D012694:Serine; D014533:Uridine Diphosphate Glucose Dehydrogenase; D000409:Alanine