Hello, van der Waals interactions are very weak, this is why we usually speak about van der Waals contacts rather than interactions. These are usually in the range of 3.5-3.8/4 Å (smaller than that may indicate a close contact or steric clash of an atomic model under refinement), corresponding to the packing of the van der Waals spheres of the individual atoms. In hydrogen bond interactions, the term “interaction” normally implies sharing a hydrogen atom between two polar residues, for example between the hydroxyl group of a threonine side chain with a carbonyl group of the main chain peptide backbone; in there one should take into account the geometry as well (e.g. ~120°-180° is favorable, 90° is not). Note that some positions such as Calpha-H can be slightly polarized (these contribute to bifurcated H-bonds in beta sheets for example, see e.g. https://www.ncbi.nlm.nih.gov/pubmed/12220491 ). In the context of series of van der Waals contacts between hydrophobic residues there can be additive effects of the weak interactions with then sum up, but in this context one should also consider entropic effects such as de-solvatation which becomes favorable energetically.
Hope this helps. Best regards, Bruno ########################################################################### Bruno P. Klaholz Centre for Integrative Biology Institute of Genetics and of Molecular and Cellular Biology 67404 ILLKIRCH FRANCE http://igbmc.fr/Klaholz From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of chemocev marker Sent: 08 December 2017 07:55 To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] Van der waals force Hi I just have a basic question if the Van der waals interaction will exist between the hydrophobic residues or it can also be contributed by the polar residues as well. What distance is required for the Van der waals interaction. best Jiri
