Faculty Bibliography

The impact of structural biology on the design of ligands (agonists, antagonists and modulators) for ionotropic glutamate receptors is reviewed.

The flow of ions through cation-selective members of the pentameric ligand-gated ion channel family is inhibited by a structurally diverse class of molecules that bind to the transmembrane pore in the open state of the protein. To obtain insight into the mechanism of channel block, we have investigated the binding of positively charged inhibitors to the open channel of the bacterial homolog GLIC by using X-ray crystallography and electrophysiology. Our studies reveal the location of two regions for interactions, with larger blockers binding in the center of the membrane and divalent transition metal ions binding to the narrow intracellular pore entry. The results provide a structural foundation for understanding the interactions of the channel with inhibitors that is relevant for the entire family.

The first total synthesis of newbouldine has been achieved employing a new, reductive N-N bond forming reaction. The asymmetric synthesis confirms that the natural product is a racemate. (C) 2010 Elsevier Ltd. All rights reserved.

Genetically targeted light-activated ion channels and pumps make it possible to determine the role of specific neurons in neuronal circuits, information processing and behavior. We developed a K+-selective ionotropic glutamate receptor that reversibly inhibits neuronal activity in response to light in dissociated neurons and brain slice and also reversibly suppresses behavior in zebrafish. The receptor is a chimera of the pore region of a K+-selective bacterial glutamate receptor and the ligand-binding domain of a light-gated mammalian kainate receptor. This hyperpolarizing light-gated channel, HyLighter, is turned on by a brief light pulse at one wavelength and turned off by a pulse at a second wavelength. The control is obtained at moderate intensity. After optical activation, the photocurrent and optical silencing of activity persists in the dark for extended periods. The low light requirement and bi-stability of HyLighter represent advantages for the dissection of neural circuitry.

Hexatriene substrates substituted in the 2-position with carbonyl groups were studied in the context of catalytic 6 pi electrocyclizations. The nature of the carbonyl group and the substitution pattern on the hexatriene have significant effects on the ability of these substrates to succumb to catalysis. A novel 2-formyl hexatriene dimerization was observed. The first example of a catalytic asymmetric carba-6 pi electrocyclization is reported along with the discovery of an unusual kinetic resolution via a catalytic photochemical electrocyclic ring-opening.