Department of Biochemistry
4-403 BSB
Iowa City, IA 52242-1109 USA phone: 877-846-8569
or 319-335-7932
fax: (319) 335-9570
biochem@uiowa.edu
Department of Biochemistry
Faculty Profiles
S.Ramaswamy, Ph.D
Associate Professor
Current Research
Our work focuses on structural enzymology and structure function relationship in proteins. There are two systems that have been the main focus: Alcohol dehydrogenase and Naphthalene dioxygenase.
Alcohol dehydrogenase is a well studied enzyme biochemically as well as structurally. It gives us therefore an excellent platform to ask detailed mecahnistic questions. Using a combination of mutagenesis studies and enzymology done in the laboratory of Prof. Bryce Plapp with high resolution structural studies using x-ray crystallography it has been possible to demonstrate the flexibility of the amino acids in the active site. The dynamic nature of proteins and the contribution of dynamics to the function of the protein is being probed. Atomic resolution structure determination of horse liver alcohol dehydrogenase as well as structures of related alcohol dehydrogenase is presently in progress.
Dioxygenases are the principal agents responsible for the turnover of aromatic hydrocarbons and related compounds in nature (Dagley, 1986). The initial reaction in the degradation of many aromatic compounds is catalyzed by multicomponent aromatic ring hydroxylating dioxygenase systems which add both atoms of dioxygen to the aromatic ring. Many of these enzymes are characterized by the extensive range of substrates they can oxidize and the different types of reactions catalyzed with different substrates . Naphthalene dioxygenase,NDO, for instance catalyzes the reaction
naphthalene + NAD(P)H + H+ + O2 ---> cis-naphthalene dihydrodiol + NAD(P)+,
It also catalyses monohydroxylation, desaturation, O- and N-dealkylation and sulfoxidation reactions. Since the determination of the 3-dimensional structure of the enzyme by X-ray crystallography we have done structures of the enzyme complexed with various stubstrates/substrate analogs/products and intermediates in an attempt to elucidate the mecahanism of action. Present work involves continued work on the mecahnism as well as structures of mutants in order to be able engineer the protein to taylor made applications (e.g. For the production of chiral synthons). This work is being carried out in collaboration with the laboratory of Prof. David Gibson in the Microbiology department.
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