Interaction of the interdigitated DPPG or DPPG/DMPC bilayer with human erythrocyte band 3: differential scanning calorimetry and fluorescence studies
✍ Scribed by Ping-yuan Wang; Jing-ze Lu; Jian-wen Chen; Fen Hwang
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 536 KB
- Volume
- 69
- Category
- Article
- ISSN
- 0009-3084
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✦ Synopsis
Human erythrocyte band 3 reconstituted into phospholipid vesicles has been used for studying the interaction of interdigitated lipid bilayer with an integral membrane protein. The interdigitated gel phase in DPPG/band 3 or DPPG/DMPC/band 3 systems was induced with polymyxin B (PMB) or Tris ÷. The phase transitions of the vesicles were detected with high-sensitivity differential scanning calorimetry (DSC). The results indicated that band 3 does not cause significant alterations in the interdigitated phase of phospholipids, with only a little decrease of the phase transition enthalpies. Fluorescence measurements showed that the transition of phospholipid/band 3 systems from the noninterdigitated to interdigitated phase is accompanied by marked intrinsic fluorescence changes of band 3. The interdigitated phase of DPPG or DPPG/DMPC vesicles increages the intrinsic fluorescence intensity of band 3 and significantly decreases the accessibility of certain tryptophan residues on the protein to Cs ÷.