Dear Fransico, *Salt bridges are close range electrostatic interaction which depend on conformer population.
*S.Jayashankar Research Student Institute for Biophysical Chemistry Hannover Medical School Germany. On Thu, Oct 16, 2008 at 8:21 AM, Chavas Leo <[EMAIL PROTECTED]> wrote: > Dear Francisco -- > On 15 Oct 2008, at 17:05, Francisco J. Enguita wrote: > > how > > can you define a salt-bridge within a protein structure ? > > > According to Wikipedia: > a salt bridge in proteins is "a relatively weak ionic bond between > positively and negatively charged side-chains of proteins." > > Now, at far as I understand (based on "Structure and Mechanism in Protein > Science - Alan Fersht), you have a salt bridge when two groups are making an > hydrogen bond that is favored by electrostatic interaction, electrostatic > energies being weak in water. To quote the author of the book, let say you > have the following equilibrium: > > E-NH3+ ------- OH2 + OH2 ------- -O2C-S <==> E-NH3+ ------- > -O2C-S + H2O ------- H2O > > The right-hand side equation would be more "favorable", as the > electrostatic interaction will be more stable than in the left-hand side > where both ions would be in contact with water molecules. > > HTH > > Kind regards. > > -- Leo -- > ------------------------------------------------------------ > Chavas Leonard, Ph.D. @ home > Research Associate > Marie Curie Actions Fellow > ------------------------------------------------------------ > Faculty of Life Sciences > The University of Manchester > The Michael Smith Building > Oxford Road > Manchester Lancashire > M13 9PT > ------------------------------------------------------------ > Tel: +44(0)161-275-1586 > e-mail: [EMAIL PROTECTED] > http://personalpages.manchester.ac.uk/staff/leonard.chavas/ > > >
