Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9882062 | Archives of Biochemistry and Biophysics | 2005 | 9 Pages |
Abstract
Eukaryotic phosphatidylinositol transfer proteins (PITPs) are composed predominantly of small (â¼32 kDa) soluble proteins that bind and transfer a single phospholipid, normally phosphatidylinositol or phosphatidycholine. Two forms, PITPα and PITPβ, which share approximately 80% amino acid sequence similarity, are known. Rat PITPα was labeled at specific single reactive Cys residues with I-AEDANS and used to examine PITP-membrane interactions. Upon binding to phospholipid vesicles, PITP labeled with AEDANS at the C-terminus, a region postulated to be involved in membrane binding, shows significant decreases in both steady-state and dynamic fluorescence anisotropy. In contrast, PITPs labeled with AEDANS at sites located distal to the C-terminus show increases in both steady-state and dynamic anisotropy. These results suggest that interaction of PITP with membrane surfaces leads to significant alterations in conformation and perhaps melting of the C-terminal helix.
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Authors
Jacqueline M. Tremblay, Jay R. Unruh, Carey K. Johnson, Lynwood R. Yarbrough,