Effect of secondary structure on the potential of mean force for poly-L-lysine in the alpha-Helix and beta-sheet conformations

Journal Article · Tue Oct 30 04:00:00 EST 2001 · Biophysical Chemistry

OSTI ID:837911

Grigsby, J J ^[1]; Blanch, H W; Prausnitz, J M

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1. LBNL Library

Because poly-L-lysine (PLL) can exist in the {alpha}-helix or {beta}-sheet conformation depending on solution preparation and solution conditions, PLL is a suitable candidate to probe the dependence of protein interactions on secondary structure. The osmotic second virial coefficient and weight-average molecular weight are reported from low-angle laser-light scattering measurements for PLL as a function of NaCl concentration, pH, and {alpha}-helix or {beta}-sheet content. Interactions between PLL molecules become more attractive as salt concentration increases due to screening of PLL charge by salt ions and at low salt concentration become more attractive as pH increases due to decreased net charge on PLL. The experimental results show that interactions are stronger for the {beta}-sheet conformation than for the {alpha}-helix conformation. A spherically-symmetric model for the potential of mean force is used to account for specific interactions not described by DLVO theory and to show how differences in secondary structure affect PLL interactions.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE Director, Office of Science. Office of Basic Energy Sciences. Division of Chemical Sciences; National Science Foundation (US)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 837911
• Report Number(s): LBNL--49230
• Journal Information: Biophysical Chemistry, Journal Name: Biophysical Chemistry Journal Issue: 2 Vol. 99
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
59 BASIC BIOLOGICAL SCIENCES
MOLECULAR WEIGHT
PROBES
PROTEINS
SCATTERING