1u81

From Proteopedia

---

Revision as of 17:26, 12 November 2007

proteopedia linkproteopedia link

spinqualitylabelsall models 1u81 Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Delta-17 Human ADP Ribosylation Factor 1 Complexed with GDP

Overview

Conformational changes associated with nucleotide exchange or truncation, of the N-terminal alpha-helix of human Arf1 have been investigated by, using forms of easily acquired NMR data, including residual dipolar, couplings and amide proton exchange rates. ADP-ribosylation factors (Arfs), are 21-kDa GTPases that regulate aspects of membrane traffic in all, eukaryotic cells. An essential component of the biological actions of Arfs, is their ability to reversibly bind to membranes, a process that involves, exposure of the myristoylated N-terminal amphipathic alpha-helix upon, activation and GTP binding. Deletion of this helix results in a protein, termed Delta17Arf1, that has a reduced affinity for GDP and the ability to, bind GTP in the absence of lipids or detergents. Previous studies, comparing crystal structures for Arf1.GDP and Delta17Arf1.GTP, identified, several regions of structural variation and suggested that these be, associated with nucleotide exchange rather than removal of the N-terminal, helix. However, separation of conformational changes because of nucleotide, binding and N-terminal truncation cannot be addressed in comparing these, structures, because both the bound nucleotide and the N terminus differ., Resolving the two effects is important as any structural changes involving, the N terminus may represent membrane-mediated conformational adjustments, that precede GTP binding. Results from NMR experiments presented here on, Arf1.GDP and Delta17Arf1.GDP in solution reveal substantial structural, differences that can only be associated with N-terminal truncation.

About this Structure

1U81 is a Single protein structure of sequence from Homo sapiens with MG and GDP as ligands. Full crystallographic information is available from OCA.

Reference

Conformational changes in human Arf1 on nucleotide exchange and deletion of membrane-binding elements., Seidel RD 3rd, Amor JC, Kahn RA, Prestegard JH, J Biol Chem. 2004 Nov 12;279(46):48307-18. Epub 2004 Aug 12. PMID:15308674

Page seeded by OCA on Mon Nov 12 19:32:35 2007