| Distance dependence and salt sensitivity of pairwise, coulombic interactions in a protein. | |
| | |
MedLine Citation:
|
PMID: 11967358 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Histidine pK(a) values were measured in charge-reversal (K78E, K97E, K127E, and K97E/K127E) and charge-neutralization (E10A, E101A, and R35A) mutants of staphylococcal nuclease (SNase) by (1)H-NMR spectroscopy. Energies of interaction between pairs of charges (DeltaG(ij)) were obtained from the shifts in pK(a) values relative to wild-type values. The data describe the distance dependence and salt sensitivity of pairwise coulombic interactions. Calculations with a continuum electrostatics method captured the experimental DeltaG(ij) when static structures were used and when the protein interior was treated empirically with a dielectric constant of 20. The DeltaG(ij) when r(ij) < or = 10 A were exaggerated slightly in the calculations. Coulomb's law with a dielectric constant near 80 and a Debye-Hückel term to account for screening by the ionic strength reproduced the salt sensitivity and distance dependence of DeltaG(ij) as well as the structure-based method. In their interactions with each other, surface charges behave as if immersed in water; the Debye length describes realistically the distance where interactions become negligible at a given ionic strength. On average, charges separated by distances (r(ij)) approximately 5 A interacted with DeltaG(ij) approximately 0.6 kcal/mole in 0.01 M KCl, but DeltaG(ij) decayed to < or =0.10 kcal/mole when r(ij) = 20 A. In 0.10 M KCl, DeltaG(ij) approximately 0.10 kcal/mole when r(ij) = 10 A. In 1.5 M KCl, only short-range interactions with r(ij) < or = 5 A persisted. Although at physiological ionic strengths the interactions between charges separated by more than 10 A are extremely weak, in situations where charge imbalance exists many weak interactions can cumulatively produce substantial effects. |
| | |
Authors:
|
Kelly K Lee; Carolyn A Fitch; Bertrand García-Moreno E |
Related Documents
:
|
41238 - Hydrophilic region of lecithin membranes studied by bromothymol blue and effects of an ... 21139138 - Planar patch clamp approach to characterize ionic currents from intact lysosomes. 18192348 - Electrostatic free energy landscapes for dna helix bending. 12188718 - Electrostatic interaction between two aqueous microdroplets in an apolar medium. 11542758 - Physical determinants of radiation sensitivity in bacterial spores. 20309648 - Release of metal ions from orthodontic appliances by in vitro studies: a systematic lit... |
Publication Detail:
|
Type: Journal Article; Research Support, U.S. Gov't, Non-P.H.S. |
Journal Detail:
|
Title: Protein science : a publication of the Protein Society Volume: 11 ISSN: 0961-8368 ISO Abbreviation: Protein Sci. Publication Date: 2002 May |
Date Detail:
|
Created Date: 2002-04-22 Completed Date: 2002-09-16 Revised Date: 2009-11-18 |
Medline Journal Info:
|
Nlm Unique ID: 9211750 Medline TA: Protein Sci Country: United States |
Other Details:
|
Languages: eng Pagination: 1004-16 Citation Subset: IM |
Affiliation:
|
Department of Biophysics, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Histidine Magnetic Resonance Spectroscopy Micrococcal Nuclease / chemistry*, genetics Mutation Protein Conformation Static Electricity Structure-Activity Relationship |
| Chemical | |
Reg. No./Substance:
|
71-00-1/Histidine; EC 3.1.31.1/Micrococcal Nuclease |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Effects of molecular crowding by saccharides on alpha-chymotrypsin dimerization.
Next Document: Direct comparison of binding equilibrium, thermodynamic, and rate constants determined by surface- a...