Publication Date:
1998-09-11
Description:
The motion of single, dye-labeled protein molecules was monitored at various pH and ionic strengths within the 180-nanometer-thick evanescent-field layer at a fused-silica surface. Below the isoelectric point, molecules partitioning into the excitation region increased in number but maintained a random spatial distribution, implying that surface charge can influence the charged protein at distances beyond that of the electrical double-layer thickness. The residence times of the molecules in the interfacial layer also increased below the isoelectric point. However, immobilization on the solid surface for extended periods was not observed. Histograms of residence times exhibit nearly identical asymmetry as the corresponding elution peaks in capillary electrophoresis. These results are a direct verification of the statistical theory of chromatography at the single-molecule level, with the caveat that long-range trapping rather than adsorption is the dominant mechanism.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Xu, X H -- Yeung, E S -- New York, N.Y. -- Science. 1998 Sep 11;281(5383):1650-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Ames Laboratory-U.S. Department of Energy and Department of Chemistry, Iowa State University, Ames, IA 50011, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9733506" target="_blank"〉PubMed〈/a〉
Keywords:
Chemistry, Physical
;
Chromatography
;
Concanavalin A/*chemistry
;
Diffusion
;
Electrophoresis, Capillary
;
Fluorescence
;
Hydrogen-Ion Concentration
;
Isoelectric Point
;
Osmolar Concentration
;
Physicochemical Phenomena
;
Proteins/*chemistry
;
Rhodamines
;
Static Electricity
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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