Hi Kavya, For the purpose (at least) of specificity in their interactions, biological macromolecules differ significantly from uniform (perhaps, synthetic) materials. By and large, their surface(s) are not flat, but rather intricate (to the point that they have been described as fractal). Second point: In aqueous solutions, hydrophobic surfaces are "masqued" by clathrates (icy water molecules; see e.g. Martha Teeeter's work on crambin), so that hydrophobic interaction requires an energetically costly desolvation penalty before they can interact (see, e.g.,detailed mechanistics of "salting out" and/or hydrophobic interaction chromatography). Finally, based on both experimental and theoretical data, the very elegant work of Barry Honig (available online, cost-free: http://www.upch.edu.pe/facien/fc/dbmbqf/zimic/cursos/modelamiento%202005/articulos/7%20Interacciones%20de%20Van%20der%20Waals/Aromatic-aromatic%20interactions%20and%20protein%20stability.%20Invest.pdf) clearly shows that are two distinct, energetically shared, contributions in the hydrophobic "interactions" of biological molecules: (1) genuine "hydrophobic effect" and (2) van der Waals contributions, roughly 50% each, plus a "short distance" desolvation penalty. Therefore, as done in several earlier studies, I suggest that hydrophobic interactions, in biological molecules that bear both polar and non polar accessible surfaces, are rather of the short-range type, unlike uniform materials and/or industry-synthesized organic molecules.
Best regards, Nadir Mrabet Pr. Nadir T. Mrabet Structural & Molecular Biochemistry N-gere - INSERM U-954 University of Lorraine, Nancy School of Sciences and Technologies & School of Medicine 9, Avenue de la Foret de Haye, BP 184 54505 Vandoeuvre-les-Nancy Cedex France Phone: +33 (0)3.83.68.32.73 Fax: +33 (0)3.83.68.32.79 E-mail: Nadir.Mrabet <at> univ-lorraine.fr LEGAL NOTICE Unless expressly stated otherwise, this message is confidential and may be privileged. It is intended for the addressee(s) only. Access to this E-mail by anyone else is unauthorized. If you are not an addressee, any disclosure or copying of the contents of this E-mail, or any action taken (or not taken) in reliance on it, is unauthorized and may be unlawful. If you are not an addressee, please inform the sender immediately. ----- Mail original ----- Dear users, Sorry for an off-topic question. What is the limits for hydrophobic interactions in protein? Some prefer 5Ang some prefer upto 8Ang. Any reference or suggestions are welcome. Thanking you Regards Kavya -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.
