Role of head group structure in the phase behavior of amino phospholipids. 2. Lamellar and nonlamellar phases of unsaturated phosphatidylethanolamine analogs

Biochemistry ◽  
1986 ◽  
Vol 25 (15) ◽  
pp. 4259-4267 ◽  
Author(s):  
Pamela M. Brown ◽  
John Steers ◽  
Sek Wen Hui ◽  
Philip L. Yeagle ◽  
John R. Silvius
Keyword(s):  
Phase Behavior ◽  
Group Structure ◽  
Head Group

scholarly journals Simulation Study of the Structure and Phase Behavior of Ceramide Bilayers and the Role of Lipid Headgroup Chemistry

2013 ◽  
Vol 9 (11) ◽  
pp. 5116-5126 ◽  
Author(s):  
Shan Guo ◽  
Timothy C. Moore ◽  
Christopher R. Iacovella ◽  
L. Anderson Strickland ◽  
Clare McCabe
Keyword(s):  
Phase Behavior ◽  
Simulation Study

Self-assembling systems based on amphiphilic alkyltriphenylphosphonium bromides: Elucidation of the role of head group

2012 ◽  
Vol 367 (1) ◽  
pp. 327-336 ◽  
Author(s):  
Gulnara A. Gainanova ◽  
Guzalia I. Vagapova ◽  
Victor V. Syakaev ◽  
Alsu R. Ibragimova ◽  
Farida G. Valeeva ◽  
...  
Keyword(s):  
Head Group ◽  
Self Assembling

Electron Transport from QA to Thymoquinone in a Synechococcus Oxygen-Evolving Photosystem II Preparation: Role of QB and Binding Affinity of Thymoquinone to the QB Site

1993 ◽  
Vol 48 (3-4) ◽  
pp. 174-178 ◽  
Author(s):  
Kazuhiko Satoh ◽  
Yasuhiro Kashino ◽  
Hiroyuki Koike
Keyword(s):  
Binding Affinity ◽  
Turnover Rate ◽  
Side Chain ◽  
Head Group ◽  
Binding Affinities ◽  
Ps Ii ◽  
Thermophilic Cyanobacteria ◽  
High Concentrations ◽  
Oxygen Evolving

Abstract We have recently shown that binding affinities of benzoquinones can be estimated by two methods in photosystem (PS) II particles (K. Satoh et al., Biochim. Biophys. Acta 1102, 45-52 (1992)). Using these methods we calculated the binding affinity of thymoquinone (2-methyl-5-isopropyl-p-benzoquinone) to the QB site and studied how the quinone accepts electrons in oxygen-evolving PS II particles isolated from the thermophilic cyanobacteria, Synechococcus elongatus and S. vulcanus. The results are as follows: (1) The binding constant of thymoqui­ none to the QB site determined by several methods was around 0.33 mᴍ . (2) At low thymoquinone concentrations the quinone was supposed to accept electrons via QB-plastoquinone, whereas at high concentrations the quinone seemed to bind to the QB site and accept an electron directly from Q-A. Lower rates of photoreduction of the quinone at high concentrations were attributed to a slower turnover rate of the quinone at the QB site than that of endogenous plastoquinone. (3) A model for the function of plastoquinone at the QB site, which can explain all the results, was presented. According to this model, the plastoquinone molecule at the QB site is not replaced by another plastoquinone molecule. Instead, it transfers electrons to pool plastoquinone molecules by turning over its head group but remaining its long side chain bound to the PS II complexes.

Role of Glycosphingolipids in HIV-1 Entry: Requirement of Globotriosylceramide (Gb3) in CD4/CXCR4-dependent Fusion

1999 ◽  
Vol 19 (4) ◽  
pp. 317-325 ◽  
Author(s):  
Anu Puri ◽  
Peter Hug ◽  
Kristine Jernigan ◽  
Patrick Rose ◽  
Robert Blumenthal
Keyword(s):  
Structural Analysis ◽  
Cell Fusion ◽  
Envelope Glycoprotein ◽  
Human Erythrocyte ◽  
Head Group ◽  
Specific Interactions ◽  
Cd4 Cells ◽  
Fusion Site ◽  
Hiv 1

We have recently shown that addition of human erythrocyte glycosphingolipids (GSL) to non-human CD4+ or GSL-depleted human CD4+ cells rendered those cells susceptible to gp120-gp41-mediated cell fusion (Puri et al., BBRC, 1998). One GSL fraction (Fraction 3) isolated from human erythrocyte GSL mixture exhibited the highest recovery of fusion following incorporation into CD4+ non-human and GSL-depleted HeLa-CD4 cells (HeLa-CD4/GSL-). Structural analysis of Fraction 3 showed that this GSL had identical head group as the known GSL, Gal(α1→4)Gal(β1→4)Glc-Ceramide (Gb3) (Puri et al., PNAS, 1998). Here we report that presence of Gb3 in CD4+/CXCR4+ cells but not CD4+/CXCR4- cells allows fusion with HIV-1Lai-envelope glycoprotein expressing cells (TF228). Therefore, Gb3 functions in conjunction with HIV-1 co-receptor, CXCR4 to promote fusion. We propose that Gb3 functions by recruiting CD4 and/or CXCR4 at the fusion site through structurally specific interactions.

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