1uw5: Difference between revisions

Phosphatidylinositol transfer protein alpha (PITPalpha) selectively, transports and promotes exchange of phosphatidylinositol (PI) and, phosphatidylcholine (PC) between lipid bilayers. In higher eukaryotes, PITPalpha is required for cellular functions such as phospholipase, C-mediated signaling, regulated exocytosis, and secretory vesicle, formation. We have determined the crystal structure of human PITPalpha, bound to its physiological ligand, PI, at 2.95 A resolution. The structure, identifies the critical side chains within the lipid-headgroup binding, pocket that define the exquisite specificity for PI. Mutational analysis, of the PI binding pocket is in good agreement with the structural data and, allows manipulation of functional properties of PITPalpha. Surprisingly, there are no major conformational differences between PI- and PC-loaded, PITPalpha, despite previous predictions. In the crystal, PITPalpha-PI is, dimeric, with two identical dimers in the asymmetric unit. The dimer, interface masks precisely the sequence we identify as contributing to, PITPalpha membrane interaction. Our structure represents a soluble, transport-competent form of PI-loaded PITPalpha.

1UW5 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with PIE as [http://en.wikipedia.org/wiki/ligand ligand]. Structure known Active Site: PI1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1UW5 OCA].  

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