title: Structure and engineering of L-arabinitol 4-dehydrogenase from Neurospora crassa.
abstract: L-arabinitol 4-dehydrogenase (LAD) catalyzes the conversion of l-arabinitol into l-xylulose with concomitant NAD(+) reduction. It is an essential enzyme in the development of recombinant organisms that convert l-arabinose into fuels and chemicals using the fungal l-arabinose catabolic pathway. Here we report the crystal structure of LAD from the filamentous fungus Neurospora crassa at 2.6 A resolution. In addition, we created a number of site-directed variants of N. crassa LAD that are capable of utilizing NADP(+) as cofactor, yielding the first example of LAD with an almost completely switched cofactor specificity. This work represents the first structural data on any LAD and provides a molecular basis for understanding the existing literature on the substrate specificity and cofactor specificity of this enzyme. The engineered LAD mutants with altered cofactor specificity should be useful for applications in industrial biotechnology.
authors.affiliation: Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Bae
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Sullivan
authors.forename: Huimin
authors.initials: H
authors.lastname: Zhao
authors.forename: Satish K
authors.initials: SK
authors.lastname: Nair
mesh_terms: D000595:Amino Acid Sequence; D002384:Catalysis; D018360:Crystallography, X-Ray; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009243:NAD / Q000378:metabolism; D009492:Neurospora crassa / Q000201:enzymology*; D011487:Protein Conformation; D015202:Protein Engineering; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013401:Sugar Alcohol Dehydrogenases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013402:Sugar Alcohols / Q000378:metabolism
chemical_list: D013402:Sugar Alcohols; D009243:NAD; D013401:Sugar Alcohol Dehydrogenases; C440029:L-arabinitol 4-dehydrogenase; C014999:arabitol