Characterization of hydrophobic-ligand-binding proteins of Taenia solium that are expressed specifically in the adult stage

Parasitology ◽  
2012 ◽  
Vol 139 (10) ◽  
pp. 1361-1374 ◽  
Author(s):  
M. RAHMAN ◽  
E.-G. LEE ◽  
S.-H. KIM ◽  
Y.-A. BAE ◽  
H. WANG ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Binding Proteins ◽  
Unsaturated Fatty Acids ◽  
Genomic Structure ◽  
Taenia Solium ◽  
Binding Activity ◽  
Hymenolepis Diminuta ◽  
Lipid Uptake ◽  
Sequence Identity ◽  
Hydrophobic Ligand

SUMMARYTaenia solium, a causative agent of taeniasis and cysticercosis, has evolved a repertoire of lipid uptake mechanisms. Proteome analysis of T. solium excretory-secretory products (TsESP) identified 10 kDa proteins displaying significant sequence identity with cestode hydrophobic-ligand-binding-proteins (HLBPs). Two distinct 362- and 352-bp-long cDNAs encoding 264- and 258-bp-long open reading frames (87 and 85 amino acid polypeptides) were isolated by mining the T. solium expressed sequence tags and a cDNA library screening (TsHLBP1 and TsHLBP2; 94% sequence identity). They clustered into the same clade with those found in Moniezia expansa and Hymenolepis diminuta. Genomic structure analysis revealed that these genes might have originated from a common ancestor. Both the crude TsESP and bacterially expressed recombinant proteins exhibited binding activity toward 1-anilinonaphthalene-8-sulfonic acid (1,8-ANS), which was competitively inhibited by oleic acid. The proteins also bound to cis-parinaric acid (cPnA) and 16-(9-anthroyloxy) palmitic acid (16-AP), but showed no binding activity against 11-[(5-dimethylaminonaphthalene-1-sulfonyl) amino] undecanoic acid (DAUDA) and dansyl-DL-α-aminocaprylic acid (DACA). Unsaturated fatty acids (FAs) showed greater affinity than saturated FAs. The proteins were specifically expressed in adult worms throughout the strobila. The TsHLBPs might be involved in uptake and/or sequestration of hydrophobic molecules provided by their hosts, thus contributing to host-parasite interface interrelationships.

scholarly journals The Unique C Termini of Orthopoxvirus Gamma Interferon Binding Proteins Are Essential for Ligand Binding

2006 ◽  
Vol 80 (21) ◽  
pp. 10675-10682 ◽  
Author(s):  
Anthony A. Nuara ◽  
Hongdong Bai ◽  
Nanhai Chen ◽  
R. Mark L. Buller ◽  
Mark R. Walter
Keyword(s):  
Amino Acids ◽  
Ligand Binding ◽  
Binding Proteins ◽  
Cysteine Residue ◽  
Binding Activity ◽  
Gamma Interferon ◽  
Amino Acid Residues ◽  
Ordered Structures ◽  
Binding Domains ◽  
Ifn Γ

ABSTRACT The orthopoxviruses ectromelia virus (ECTV) and vaccinia virus (VACV) express secreted gamma interferon binding proteins (IFN-γBPs) with homology to the ligand binding domains of the host's IFN-γ receptor (IFN-γR1). Homology between these proteins is limited to the extracellular portions of the IFN-γR1 and the first ∼200 amino acids of the IFN-γBPs. The remaining 60 amino acids at the C termini of the IFN-γBPs contain a single cysteine residue shown to be important in covalent dimerization of the secreted proteins. The function of the remaining C-terminal domain (CTD) has remained elusive, yet this region is conserved within all orthopoxvirus IFN-γBPs. Using a series of C-terminal deletion constructs, we have determined that the CTD is essential for IFN-γ binding despite having no predicted homology to the IFN-γR1. Truncation of the ECTV IFN-γBP by more than two amino acid residues results in a complete loss of binding activity for both murine IFN-γ and human IFN-γ (hIFN-γ), as measured by surface plasmon resonance (SPR) and bioassay. Equivalent truncation of the VACV IFN-γBP resulted in comparable loss of hIFN-γ binding activity by SPR. Full-length IFN-γBPs were observed to form higher-ordered structures larger than the previously reported dimers. Mutants that were unable to bind IFN-γ with high affinity in SPR experiments failed to assemble into these higher-ordered structures and migrated as dimers. We conclude that the unique CTD of orthopoxvirus IFN-γBPs is important for the assembly of covalent homodimers as well as the assembly of higher-ordered structures essential for IFN-γ binding.

scholarly journals Gastrotropin: not an enterooxyntin but a member of a family of cytoplasmic hydrophobic ligand binding proteins

1989 ◽  
Vol 264 (34) ◽  
pp. 20248-20254
Author(s):  
I Gantz ◽  
S.F. Nothwehr ◽  
M Lucey ◽  
J.C. Sacchettini ◽  
J DelValle ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Binding Proteins ◽  
Hydrophobic Ligand

Distinct Modulation of Wild-Type and Selective Gene Mutated Vitamin D Receptor by Essential Poly Unsaturated Fatty Acids

2021 ◽  
Vol 21 ◽  
Author(s):  
Hari Balaji ◽  
Selvaraj Ayyamperuma ◽  
Niladri Saha ◽  
Shyam Sundar Pottabathula ◽  
Jubie Selvaraj ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Vitamin D ◽  
Ligand Binding ◽  
Vitamin D Deficiency ◽  
Binding Affinity ◽  
Unsaturated Fatty Acids ◽  
Binding Domain ◽  
Ligand Binding Domain ◽  
Binding Energies ◽  
Wild Type

: Vitamin-D deficiency is a global concern. Gene mutations in the vitamin D receptor’s (VDR) ligand binding domain (LBD) variously alter the ligand binding affinity, heterodimerization with retinoid X receptor (RXR) and inhibit coactivator interactions. These LBD mutations may result in partial or total hormone unresponsiveness. A plethora of evidence report that selective long chain polyunsaturated fatty acids (PUFAs) including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA) bind to the ligand-binding domain of VDR and lead to transcriptional activation. We therefore hypothesize that selective PUFAs would modulate the dynamics and kinetics of VDRs, irrespective bioactive of vitamin-D binding. The spatial arrangements of the selected PUFAs in VDR active site were examined by in-silico docking studies. The docking results revealed that PUFAs have fatty acid structure-specific binding affinity towards VDR. The calculated EPA, DHA & AA binding energies (Cdocker energy) were lesser compared to vitamin-D in wild type of VDR (PDB id: 2ZLC). Of note, the DHA has higher binding interactions to the mutated VDR (PDB id: 3VT7) when compared to the standard Vitamin-D. Molecular dynamic simulation was utilized to confirm the stability of potential compound binding of DHA with mutated VDR complex. These findings suggest the unique roles of PUFAs in VDR activation and may offer alternate strategy to circumvent vitamin-D deficiency.

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