Crystal structure of complement protein C8γ in complex with a peptide containing the C8γ binding site on C8α: Implications for C8γ ligand binding

Abstract The periplasmic ligand-binding protein ChoX is part of the ABC transport system ChoVWX that imports choline as a nutrient into the soil bacterium Sinorhizobium meliloti. We have recently reported the crystal structures of ChoX in complex with its ligands choline and acetylcholine and the structure of a fully closed but substrate-free state of ChoX. This latter structure revealed an architecture of the ligand-binding site that is superimposable to the closed, ligand-bound form of ChoX. We report here the crystal structure of ChoX in an unusual, ligand-free conformation that represents a semi-closed form of ChoX. The analysis revealed a subdomain movement in the N-lobe of ChoX. Comparison with the two well-characterized substrate binding proteins, MBP and HisJ, suggests the presence of a similar subdomain in these proteins.

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Corrigendum to “Binding site and interlobe interactions of the ionotropic glutamate receptor GluK3 ligand binding domain revealed by high resolution crystal structure in complex with (S)-glutamate” [J. Struct. Biol. 176 (2011) 307–314]

Journal of Structural Biology ◽

10.1016/j.jsb.2013.10.001 ◽

2013 ◽

Vol 184 (2) ◽

pp. 381 ◽

Cited By ~ 2

Author(s):

Raminta Venskutonytė ◽

Karla Frydenvang ◽

Michael Gajhede ◽

Lennart Bunch ◽

Darryl S. Pickering ◽

...

Keyword(s):

Crystal Structure ◽

High Resolution ◽

Ligand Binding ◽

Binding Site ◽

Glutamate Receptor ◽

Binding Domain ◽

Ligand Binding Domain ◽

Ionotropic Glutamate Receptor

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Simultaneous inhibition of anti-coagulation and inflammation: crystal structure of phospholipase A2complexed with indomethacin at 1.4 Å resolution reveals the presence of the new common ligand-binding site

Journal of Molecular Recognition ◽

10.1002/jmr.960 ◽

2009 ◽

Vol 22 (6) ◽

pp. 437-445 ◽

Cited By ~ 23

Author(s):

Nagendra Singh ◽

Ramasamy Prem Kumar ◽

Sanjit Kumar ◽

Sujata Sharma ◽

Rafia Mir ◽

...

Keyword(s):

Crystal Structure ◽

Ligand Binding ◽

Binding Site ◽

Ligand Binding Site ◽

Simultaneous Inhibition

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Critical residues for ligand binding in blade 2 of the propeller domain of the integrin αIIb subunit

Thrombosis and Haemostasis ◽

10.1160/th03-06-0392 ◽

2004 ◽

Vol 91 (01) ◽

pp. 111-118 ◽

Cited By ~ 4

Author(s):

Tatsushiro Tamura ◽

Jun Yamanouchi ◽

Shigeru Fujita ◽

Takaaki Hato

Keyword(s):

Crystal Structure ◽

Ligand Binding ◽

Binding Site ◽

Thrombus Formation ◽

Direct Interaction ◽

Binding Pocket ◽

Crystal Structure Analysis ◽

Site Directed Mutagenesis ◽

Structural Basis ◽

Critical Residues

SummaryLigand binding to integrin αIIbβ3 is a key event of thrombus formation. The propeller domain of the αIIb subunit has been implicated in ligand binding. Recently, the ligand binding site of the αV propeller was determined by crystal structure analysis. However, the structural basis of ligand recognition by the αIIb propeller remains to be determined. In this study, we conducted site-directed mutagenesis of all residues located in the loops extending above blades 2 and 4 of the αIIb propeller, which are spatially close to, but distinct from, the loops that contain the binding site for an RGD ligand in the crystal structure of the αV propeller. Replacement by alanine of Q111, H112 or N114 in the loop within the blade 2 (the W2:2-3 loop in the propeller model) abolished binding of a ligand-mimetic antibody and fibrinogen to αIIbβ3 induced by different types of integrin activation including activation of αIIbβ3 by β3 cytoplasmic mutation. CHO cells stably expressing recombinant αIIbβ3 bearing Q111A, H112A or N114A mutation did not exhibit αIIbβ3mediated adhesion to fibrinogen. According to the crystal structure of αVβ3, the αV residue corresponding to αIIbN114 is exposed on the integrin surface and close to the RGD binding site. These results suggest that the Q111, H112 and N114 residues in the loop within blade 2 of the αIIb propeller are critical for ligand binding, possibly because of direct interaction with ligands or modulation of the RGD binding pocket.

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