University Magazine Spring 2002

This is the official magazine for RIT Alumni. Issued thrice a year in spring, fall and winter. Printing began in 1999

Ion Permeation in the NanC Porin from Escherichia coli: Free Energy Calculations along Pathways Identified by Coarse-Grain Simulations

Using the X-ray structure of a recently discovered bacterial protein, the <i>N</i>-acetylneuraminic acid-inducible channel (NanC), we investigate computationally K⁺ and Cl^– ions’ permeation. We identify ion permeation pathways that are likely to be populated using coarse-grain Monte Carlo simulations. Next, we use these pathways as reaction coordinates for umbrella sampling-based free energy simulations. We find distinct tubelike pathways connecting specific binding sites for K⁺ and, more pronounced, for Cl^– ions. Both ions permeate the porin preserving almost all of their first hydration shell. The calculated free energy barriers are <i>G</i>^# ≈ 4 kJ/mol and <i>G</i>^# ≈ 8 kJ/mol for Cl^– and K⁺, respectively. Within the approximations associated with these values, discussed in detail in this work, we suggest that the porin is slightly selective for Cl^– versus K⁺. Our suggestion is consistent with the experimentally observed weak Cl^– over K⁺ selectivity. A rationale for the latter is suggested by a comparison with previous calculations on strongly anion selective porins

University Magazine Fall 2006

This is the official magazine for RIT Alumni. Issued thrice a year in spring, fall and winter. Printing began in 1999

University Magazine Winter 2003

This is the official magazine for RIT Alumni. Issued thrice a year in spring, fall and winter. Printing began in 1999

University Magazine Fall 2010

This is the official magazine for RIT Alumni. Issued thrice a year in spring, fall and winter. Printing began in 1999

University Magazine Winter 2012

This is the official magazine for RIT Alumni. Issued thrice a year in spring, fall and winter. Printing began in 1999

University Magazine Fall 2014

This is the official magazine for RIT Alumni. Issued thrice a year in spring, fall and winter. Printing began in 1999

University Magazine Spring 2014

This is the official magazine for RIT Alumni. Issued thrice a year in spring, fall and winter. Printing began in 1999

University Magazine Winter 2013

This is the official magazine for RIT Alumni. Issued thrice a year in spring, fall and winter. Printing began in 1999

University Magazine Winter 2014

This is the official magazine for RIT Alumni. Issued thrice a year in spring, fall and winter. Printing began in 1999