HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Zucker, S. D. Articles by Sterritt, C. Search for Related Content PubMed PubMed Citation Articles by Zucker, S. D. Articles by Sterritt, C. Social Bookmarking                      What's this?

Journal of Lipid Research, Vol. 42, 1377-1388, September 2001
Copyright © 2001 by Lipid Research, Inc.

Original Article

Localization of bilirubin in phospholipid bilayers by parallax analysis of fluorescence quenching

Correspondence to: Stephen D. Zucker, To whom correspondence should be addressed., zuckersd{at}email.uc.edu (E-mail)

It has been proposed that the neurotoxicity observed in severely jaundiced infants results from the binding of unconjugated bilirubin to nerve cell membranes. However, despite potentially important clinical ramifications, there remains significant controversy regarding the physical nature of bilirubin-membrane interactions. We used the technique of parallax analysis of fluorescence quenching (Chattopadhyay, A., and E. London. 1987. Biochemistry. 26: 39;–45) to measure the depth of penetration of bilirubin in model phospholipid bilayers. The localization of unconjugated bilirubin and ditaurobilirubin within small unilamellar vesicles composed of dioleoylphosphatidylcholine was determined through an analysis of the quenching of bilirubin fluorescence by spin-labeled phospholipids, and by bilirubin-mediated quenching of a series of anthroyloxy fatty acid probes at various depths within the membrane bilayer. Findings were further verified with potassium iodide as an aqueous quencher.

Our results indicate that, at pH 10, unconjugated bilirubin localizes approximately 20 Å from the bilayer center, in the region of the polar head groups. Further analyses suggest a modest influence of pH, membrane cholesterol content, and vesicle diameter on the bilirubin penetration depth. Taken together, these data support that, under physiologic conditions, bilirubin localizes to the polar region of phospholipid bilayers, near the membrane-water interface. — Zucker, S. D., W. Goessling, E. J. Bootle, and C. Sterritt. Localization of bilirubin in phospholipid bilayers by parallax analysis of fluorescence quenching. J. Lipid Res. 2001. 42: 1377;–1388.

Supplementary key words: membranes, resonance energy transfer, kernicterus, cholesterol, ditaurobilirubin, quantum yield, potassium iodide, binding affinity

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				C. M. P. Rodrigues, S. Sola, R. E. Castro, P. A. Laires, D. Brites, and J. J. G. Moura Perturbation of membrane dynamics in nerve cells as an early event during bilirubin-induced apoptosis J. Lipid Res., June 1, 2002; 43(6): 885 - 894. [Abstract] [Full Text] [PDF]