Susquehanna Valley Section

October 2007 Meeting

The three hundred and seventy-second meeting of the Section will be held on Wednesday, 10 October 2007 at Wilkes University. A dinner will be followed by a guest presentation entitled "Molecular Doorstop - Structure and Functional Role of the N-terminal Domain of the P. aeruginosa Rhomboid" by Dr. Ranajeet Ghose from CUNY-Brooklyn.

Dinner: 6:00 - 7:15 p.m. Room 214 of the Martz Center
Meeting and Presentation: 7:30 p.m. in Room 270 of the Stark Learning Center

Dinner: Dinner entrees will be a buffet dinner including a vegetarian option and dessert. The cost will be $13 per person. Please RSVP to Ms Mary Lou Gillespie by email mary.gillespie@wilkes.edu or phone 570.408.4750 by 4:30 p.m. Friday, 5 October 2007. A limited number of late reservations may be accomodated, but your early R.S.V.P. will assist us in finalizing the catering arrangements.

Directions and parking: see below

Molecular Doorstop - Structure and Functional Role of the N-terminal Domain of the P. aeruginosa Rhomboid
In regulated intramembrane proteolysis (RIP), membrane proteins are specifically proteolyzed within their transmembrane region resulting in the release of soluble fragments that relocate within the intracellular or extracellular medium, where they can elicit a biological response. The intramembrane-cleaving proteases (ICLiPs) constitute a novel a class of integral membrane proteins that are divided into √ aspartic proteases, metalloproteases and serine proteases based on their putative catalytic residues. Scant information is available on the molecular details of the functional regulation of these ICLiPs. The rhomboids, the only serine proteases discovered so far, are unique in that no additional effecter molecules are required and the presence of substrate is sufficient for activity. Thus obtaining a clear understanding of the substrate specificity, mechanism of action and mode of regulation of rhomboids could have relevant implications for other intramembrane proteases, such as g-secretase, where substrate recognition and peptide bond selectivity have serious implications in the pathogenesis of Alzheimer disease. We present here the solution structure of the cytosolic N-terminal domain (NRho) of P. aeruginosa Rhomboid. We find evidence that NRho is capable of strong and specific association with detergent micelles that mimic the membrane/water interface. Nuclear magnetic resonance (NMR) relaxation measurements on NRho reveal structural fluctuations on the ms-ms timescale in regions including and contiguous to those implicated in membrane interaction. This structural plasticity may facilitate the ability of NRho to recognize and associate with membranes. We suggest that NRho plays a role in scissile peptide bond selectivity by optimally positioning the Rhomboid active site relative to the membrane plane.

Dr. Ghose received degrees in Chemistry from Presidency College, Calcutta, India (B Sc. in 1990) and from Indian Institute of Technology, Kanpur, India (M. Sc. in 1992). He continued his career at Yale University, New Haven, CT where he earned his Ph. D. in Chemical Physics in 1998. He was then employed at the University of Lausanne, Lausanne, Switzerland as a Premier Asst. from 1998-1999 and later as a Postdoctoral fellow at Rockefeller University, New York, NY (1999-2002). Since 2002, he has served as an Assistant Professor and a member of the graduate faculty in Chemistry, Physics & Biochemistry for the Graduate Center of the City University of New York. The thrust of his work during his career has been the application of NMR Spectroscopy to the study of biologically important systems, biochemistry, and structural biology. He is an author on over twenty-five peer reviewed publications and has presented his work at a large number of national and international scientific meetings. Dr. Ghose has also received numerous honors including a National Merit Scholarship, the Samuel K. Bushnell Fellowship at Yale University, a National Science Foundation CAREER award and two CUNY Salute to Scholars for Outstanding Scholarly Achievement Awards.

Directions and parking:

Directions:
Take I-81 to Route 309 North (Exit 170B, Old Exit 47B). Follow Route 309 North to Exit 3 (Plains/River Street) and make a left onto River Street at the traffic light at the bottom of the exit ramp. Follow River Street south to Wilkes University (located on the left side of River St).

The Martz Ceneter is located on Franklin Street and the Stark Learning Center is on River St. mid-block between Northampton and South Streets.

Parking:
To arrive at the Marts Center turn left onto Ross Street at the 10^th traffic light after the ramp, and make a left onto Franklin Street at the next light. The Marts Center (274 South Franklin Street) will be on the right. There is a parking lot just past the gym on the left side of the street. This lot connects to the parking lot behind the Henry Student Union Building (also accessable by an entrance immediately past the Henry Student Union Building (SUB) on South St.). You may also park in most other campus lots.

Detailed directions and maps can be found at: http://www.wilkes.edu/pages/273.asp.