NMR analysis of structure and dynamics of the cytosolic tails of integrin alpha IIb beta 3 in aqueous solution.
The structural and dynamic properties of the cytosolic tails of the adhesion receptor integrin alphaIIbbeta3, fused to a coiled-coil construct via (Gly)(3) linkers, were studied in aqueous solution by nuclear magnetic resonance (NMR) spectroscopy. Both tails were largely flexible and unstructured, although, in the beta3 tail, residues Arg(724)-Ala(735) have a propensity to form a helical structure and residues Asn(744)-Tyr(747) (NPLY) have a propensity to adopt reverse-turn conformations. The mutation beta3(Y747A) disrupted this reverse-turn tendency and markedly reduced the affinity of the head domain of the cytoskeletal protein, talin for the beta3 tail. Omission of the (Gly)(3) linker connecting the coiled-coiled helices and the integrin tails lead to helix propagation into the beta3 tail extending up to eight residues. A variety of different tail constructs were made and studied to reveal tail-tail interactions, but surprisingly no significant interactions between both tails could be detected within the context of our constructs. These results provide structural insight into a highly conserved beta tail motif (NPXY/F) required for integrin signaling and highlight a second transiently structured region (residues Arg(724)-Ala(735)), which might also be of functional significance.
Ulmer
T S
TS
Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
Yaspan
B
B
Ginsberg
M H
MH
Campbell
I D
ID
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D003600:Cytosol / Q000737:chemistry*; D016023:Integrins / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D010446:Peptide Fragments / Q000737:chemistry* / Q000235:genetics; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000737:chemistry* / Q000235:genetics; D017433:Protein Structure, Secondary / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D012996:Solutions; D013329:Structure-Activity Relationship; D013816:Thermodynamics; D014867:Water
D016023:Integrins; D010446:Peptide Fragments; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D011993:Recombinant Fusion Proteins; D012996:Solutions; D014867:Water