Dataset Information

Molecular Basis of the Ligand Binding Specificity of ?v?8 Integrin.

ABSTRACT: ?v?8 is an integrin that recognizes an Arg-Gly-Asp (RGD) motif and interacts with fibronectin, vitronectin, and latent TGF-?1. We comprehensively determined the binding activity of the ?v?8 integrin toward 25 secreted proteins having an RGD motif. The ?v?8 integrin strongly bound to latent TGF-?1 but showed marginal activity for other RGD-containing proteins, including fibronectin and vitronectin. Site-directed mutagenesis of latent TGF-?1 demonstrated that the high affinity binding of ?v?8 integrin to latent TGF-?1 was defined by Leu-218 immediately following the RGD motif within the latency-associated peptide of TGF-?1. Consistent with the critical role of Leu-218 in latent TGF-?1 recognition by ?v?8 integrin, a 9-mer synthetic peptide containing an RGDL sequence strongly inhibited interactions of latent TGF-?1 with ?v?8 integrin, whereas a 9-mer peptide with an RGDA sequence was ?60-fold less inhibitory. Because ?v?3 integrin did not exhibit strong binding to latent TGF-?1 or distinguish between RGDL- and RGDA-containing peptides, we explored the mechanism by which the integrin ?8 subunit defines the high affinity binding of latent TGF-?1 by ?v?8 integrin. Production of a series of swap mutants of integrin ?8 and ?3 subunits indicated that the high affinity binding of ?v?8 integrin with latent TGF-?1 was ensured by interactions between the Leu-218 residue and the ?8 I-like domain, with the former serving as an auxiliary recognition residue defining the restricted ligand specificity of ?v?8 integrin toward latent TGF-?1. In support of this conclusion, high affinity binding toward the ?v?8 integrin was conferred on fibronectin by substitution of its RGDS motif with an RGDL sequence.

SUBMITTER: Ozawa A

PROVIDER: S-EPMC4882426 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Molecular Basis of the Ligand Binding Specificity of αvβ8 Integrin.

Ozawa Akio A Sato Yuya Y Imabayashi Tsukasa T Uemura Toshihiko T Takagi Junichi J Sekiguchi Kiyotoshi K

The Journal of biological chemistry 20160331 22

αvβ8 is an integrin that recognizes an Arg-Gly-Asp (RGD) motif and interacts with fibronectin, vitronectin, and latent TGF-β1. We comprehensively determined the binding activity of the αvβ8 integrin toward 25 secreted proteins having an RGD motif. The αvβ8 integrin strongly bound to latent TGF-β1 but showed marginal activity for other RGD-containing proteins, including fibronectin and vitronectin. Site-directed mutagenesis of latent TGF-β1 demonstrated that the high affinity binding of αvβ8 inte ...[more]

PMID: 27033701

Similar Datasets

Project description:Oxalate decarboxylase (OxDC) catalyzes the conversion of oxalate into formate and carbon dioxide in a remarkable reaction that requires manganese and dioxygen. Previous studies have shown that replacing an active-site loop segment Ser(161)-Glu(162)-Asn(163)-Ser(164) in the N-terminal domain of OxDC with the cognate residues Asp(161)-Ala(162)-Ser-(163)-Asn(164) of an evolutionarily related, Mn-dependent oxalate oxidase gives a chimeric variant (DASN) that exhibits significantly increased oxidase activity. The mechanistic basis for this change in activity has now been investigated using membrane inlet mass spectrometry (MIMS) and isotope effect (IE) measurements. Quantitative analysis of the reaction stoichiometry as a function of oxalate concentration, as determined by MIMS, suggests that the increased oxidase activity of the DASN OxDC variant is associated with only a small fraction of the enzyme molecules in solution. In addition, IE measurements show that C-C bond cleavage in the DASN OxDC variant proceeds via the same mechanism as in the wild-type enzyme, even though the Glu(162) side chain is absent. Thus, replacement of the loop residues does not modulate the chemistry of the enzyme-bound Mn(II) ion. Taken together, these results raise the possibility that the observed oxidase activity of the DASN OxDC variant arises from an increased level of access of the solvent to the active site during catalysis, implying that the functional role of Glu(162) is to control loop conformation. A 2.6 Å resolution X-ray crystal structure of a complex between oxalate and the Co(II)-substituted ΔE162 OxDC variant, in which Glu(162) has been deleted from the active site loop, reveals the likely mode by which the substrate coordinates the catalytically active Mn ion prior to C-C bond cleavage. The "end-on" conformation of oxalate observed in the structure is consistent with the previously published V/K IE data and provides an empty coordination site for the dioxygen ligand that is thought to mediate the formation of Mn(III) for catalysis upon substrate binding.

Dataset Information

Molecular Basis of the Ligand Binding Specificity of ?v?8 Integrin.

Publications

Molecular Basis of the Ligand Binding Specificity of αvβ8 Integrin.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets