Bridged Bimetallic Enzymes Are 2 heads better than 1?

We hypothesize that the unique bridged bimetallic center functions as a "superelectrophile" in a possible electrocyclic hydride transfer reaction. Our aim is to determine how this center functions, by carrying out combined quantum mechanics/molecular dynamics simulations of the reaction pathway. Our second aim is to continue our crystallographic studies of the overall mechanism by probing the role of the metal ions through site-directed mutagenesis followed by direct crystallographic observation of the Michaelis complex with sugar substrates. We use these structures to test the hypothesis that communication between the metal ions, in the form of the bridge, is essential for proper functioning of the center in hydride transfer catalysis.

Publications

Desmarais WT, Bienvenue DL, Bzymek KP, Holz RC, Petsko GA, Ringe D The 1.20 A resolution crystal structure of the aminopeptidase from Aeromonas proteolytica complexed with tris: a tale of buffer inhibition.Structure (2002) 10:1063-1072.

Bienvenue DL, Mathew RS, Ringe, D, Holz RC The aminopeptidase from Aeromonas proteolytica can function as an esterase.J. Biol. Inorg. Chem. (2002) 7:129-135.

Stamper C, Bennett B, Edwards T, Holz RC, Ringe D, Petsko GA Inhibition of the aminopeptidase from Aeromonas proteolytica by L-leucinephosphonic acid. Spectroscopic and crystallographic characterization of the transition state of peptide hydrolysis.Biochemistry (2001) 40:7035-7046.

De Paola CC, Bennett B, Holz RC, Ringe D & Petsko GA 1-Butaneboronic Acid Binding to Aeromonas proteolytica Aminopeptidase: A Case of Arrested Development. Biochemsitry (1999) 38:9048-9053.

Allen KN, Lavie A, Glasfeld A, Tanada TN, Gerrity DP, Carlson SC, Farber GK, Petsko GA & Ringe D Role of the Divalent Metal Ion in Sugar Binding, Ring Opening and Isomerization by D-Xylose Isomerase: Replacement of a Catalytic Metal by an Amino-Acid. Biochemistry (1994) 33:1488-94.

Lavie A, Allen KN, Petsko GA & Ringe D X-ray crystallographic structures of D-xylose Isomerase-Substrate Complexes Position the Substrate and Provide Evidence for Metal Movement During Catalysis. Biochemistry (1994) 33:5469-80.