Apolipoprotein E: phospholipid binding studies with synthetic peptides from the carboxyl terminus

Biochemistry ◽  
1992 ◽  
Vol 31 (4) ◽  
pp. 1065-1068 ◽  
Author(s):  
James T. Sparrow ◽  
Doris A. Sparrow ◽  
Germain Fernando ◽  
Alan R. Culwell ◽  
Merry Kovar ◽  
...  
Keyword(s):  
Apolipoprotein E ◽  
Synthetic Peptides ◽  
Carboxyl Terminus ◽  
Binding Studies ◽  
Phospholipid Binding

PHOSPHOLIPID BINDING STUDIES WITH SYNTHETIC APOLIPOPROTEIN FRAGMENTS

1980 ◽  
Vol 348 (1 Lipoprotein S) ◽  
pp. 187-211 ◽  
Author(s):  
James T. Sparrow ◽  
Antonio M. Gotto
Keyword(s):  
Binding Studies ◽  
Phospholipid Binding

Factor V Binding to Multimerin 1: Modulation by Factor V Activation and Binding Sites in the Factor V C1 and C2 Domains.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 193-193
Author(s):  
Samira B. Jeimy ◽  
Mary Ann Quinn-Allen ◽  
Nola Fuller ◽  
Kenneth Segers ◽  
Alan R. Stafford ◽  
...  
Keyword(s):  
Binding Sites ◽  
Thrombin Generation ◽  
Factor V ◽  
C2 Domain ◽  
Binding Studies ◽  
C2 Domains ◽  
Phospholipid Binding ◽  
Factor Va ◽  
Plasma Factor ◽  
C1 Domain

Abstract Platelets and endothelial cells store the polymeric factor V(a) binding protein, multimerin 1 (MMRN1), for release upon agonist stimulation. In human megakaryocytes, factor V binding to MMRN1 follows plasma factor V endocytosis, resulting in stored complexes of MMRN1 and factor V in platelet α-granules. The C2 domain of the factor V light chain contains a MMRN1 binding site; however, the affinity and stoichiometry of factor V-MMRN1 binding have not been determined, direct comparisons of factor V and Va binding to MMRN1 have not been done, and potential homologous roles of C1 and C2 domain structures in MMRN1 binding have not been studied. To further explore the mechanism of factor V and Va binding to MMRN1, and the roles of B domain release and C1 domain residues in MMRN1 binding, we used surface plasmon resonance and solid-phase binding studies. Functional consequences of factor V-MMRN1 binding were tested in competitive binding assays with the soluble phospholipid 1,2-Dicaproyl-sn-glycero-3-phospho-L-serine (C6PS), and calibrated automated thrombinography (CAT). Factor V bound to MMRN1 with a higher affinity than factor Va (approximately 2 nM versus 12 nM), and a stoichiometry consistent with binding to MMRN1 trimers. The higher affinity of factor V for MMRN1 was mainly due to differences in rates of formation of a more stable, secondary complex with MMRN1. Factor V activation by thrombin dissociated bound factor V from MMRN1, consistent with the reduced affinity of factor Va for MMRN1. A panel of point mutated, B domain deleted factor V constructs were used to identify MMRN1 binding residues in the C1 domain of factor V and Va. On a three dimensional model of factor Va, these residues mapped to a large, predominantly contiguous region between the C1 and C2 domains, that overlapped residues critical for factor Va phospholipid binding and procoagulant function. Consistent with the lowered affinity of factor Va for MMRN1, C6PS significantly inhibited factor Va-MMRN1, but not factor V-MMRN1 binding (p<0.05). Overlap between the MMRN1 and phospholipid binding sites was verified by CAT assays, as MMRN1 caused dose-dependent, significant reductions in plasma thrombin generation in these assays, by increasing lag time (p<0.01), and reducing peak (p<0.01) and total thrombin generation (p<0.01). Taken together, these data indicate that the functional homologies between the C domains of factor V extend to their MMRN1 binding sites. Moreover, thrombin has modulating effects on factor V-MMRN1 binding that mimic its effects on factor VIII-von Willebrand factor binding. The affinity of factor V-MMRN1 binding could be important to promote the association of MMRN1 with factor V in platelets, until factor V release and activation for prothrombinase assembly.

scholarly journals Strain-specific and common epitopes of gonococcal pili.

1984 ◽  
Vol 160 (1) ◽  
pp. 208-221 ◽  
Author(s):  
J B Rothbard ◽  
R Fernandez ◽  
G K Schoolnik
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Synthetic Peptides ◽  
Cyanogen Bromide ◽  
Sequence Variation ◽  
Antigenic Structure ◽  
Carboxyl Terminus ◽  
Specific Epitope ◽  
Absorption Studies ◽  
Strain Ms11

The antigenic structure of gonococcal pilin, strain MS11 (Tr), was investigated by assaying the binding of antisera engendered by intact pili from strains MS11 and R10 and their two major cyanogen bromide-generated fragments, CNBr-2 (residues 9-92) and CNBr-2 (residues 93-159), to synthetic peptides corresponding to the amino acid sequence of MS11 pilin. Four peptides were synthesized corresponding to regions of sequence variation between MS11 and R10 gonococcal pilin. Antisera against the homologous pilus filament and against its CNBr-3 fragment bind peptides equivalent to residues 121-134 and 135-151, which comprise the 30 amino acid disulfide loop near the carboxyl terminus of the protein. Heterologous pili antisera did not bind these peptides. Absorption studies proved that each peptide contained an independent, strain-specific epitope. Synthetic peptides corresponding to regions of identical sequence between MS11 and R10 pilin were used in similar binding experiments to localize a weakly immunogenic, common determinant between residues 48 and 60. less than 15% of the antibodies raised against intact pili were directed at this site. Antisera raised against MS11 or R10 CNBr-2 bind a separate peptide, residues 69-80. This region is immunogenic only as a fragment, not in the intact pilus filament.

Genetics of apolipoprotein H (β2-glycoprotein I) and anionic phospholipid binding

Lupus ◽  
1998 ◽  
Vol 7 (2_suppl) ◽  
pp. 10-13 ◽  
Author(s):  
MI Kamboh ◽  
H Mehdi
Keyword(s):  
In Vitro Mutagenesis ◽  
Binding Studies ◽  
Serum Samples ◽  
Anionic Phospholipid ◽  
Phospholipid Binding ◽  
Anionic Phospholipids ◽  
Glycoprotein I ◽  
Apolipoprotein H ◽  
Genetically Determined

Apolipoprotein H (apoH; also known as β2-glycoprotein I), is an essential cofactor for the binding of certain antiphospholipid antibodies (APA) to anionic phospholipid. The gene coding for apoH is polymorphic, with the occurrence of several common alleles in the general population. This genetically determined variation can effect the binding of apoH to anionic phospholipids and consequently the production of APA. Our group has identified two common mutations at codons 306 (Cys → Gly) and 316 (Trp → Ser) in the fifth domain of apoH which affect the binding of apoH to anionic phospholipids (phosphatidylserine or cardiolipin). ApoH from serum samples homozygous for each of these mutations or compound heterozygotes for both mutations showed no binding with anionic phospholipids on ELISA. In vitro mutagenesis and transient expression of these mutations in COS-1 cells followed by cardiolipin binding studies confirmed that Gly306 and Ser316 are causative mutations. Our data indicate that the fifth domain of apoH is essential for anionic phospholipid binding and genetically determined variation in this domain can affect the production of apoH-dependent APA.

scholarly journals Phosphatidylinositol 4,5-bisphosphate directly interacts with the β and γ subunits of the sodium channel ENaC

2020 ◽  
Vol 295 (23) ◽  
pp. 7958-7969 ◽  
Author(s):  
Crystal R. Archer ◽  
Benjamin T. Enslow ◽  
Chase M. Carver ◽  
James D. Stockand
Keyword(s):  
Plasma Membrane ◽  
Synthetic Peptides ◽  
Biochemical Analysis ◽  
Carboxyl Terminus ◽  
Phosphoryl Group ◽  
Channel Activity ◽  
Microscale Thermophoresis ◽  
Local Conformation ◽  
N Terminus ◽  
Plasma Membrane Phospholipid

The plasma membrane phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2) regulates the activity of diverse ion channels to include the epithelial Na+ channel ENaC. Whether PIP2 regulation of ENaC is due to a direct phospholipid-protein interaction, remains obscure. To date, possible interaction of PIP2 with ENaC primarily has been tested indirectly through assays of channel function. A fragment-based biochemical analysis approach is used here to directly quantify possible PIP2-ENaC interactions. We find using the CIBN-CRY2 optogenetic dimerization system that the phosphoryl group positioned at carbon 5 of PIP2 is necessary for interaction with ENaC. Previous studies have implicated conserved basic residues in the cytosolic portions of β- and γ-ENaC subunits as being important for PIP2-ENaC interactions. To test this, we used synthetic peptides of these regions of β- and γ-ENaC. Steady-state intrinsic fluorescence spectroscopy demonstrated that phosphoinositides change the local conformation of the N terminus of β-ENaC, and two sites of γ-ENaC adjacent to the plasma membrane, suggesting direct interactions of PIP2 with these three regions. Microscale thermophoresis elaborated PIP2 interactions with the N termini of β- (Kd ∼5.2 μm) and γ-ENaC (Kd ∼13 μm). A weaker interaction site within the carboxyl terminus of γ-ENaC (Kd ∼800 μm) was also observed. These results support that PIP2 regulates ENaC activity by directly interacting with at least three distinct regions within the cytoplasmic domains of the channel that contain conserved basic residues. These interactions are probably electrostatic in nature, and are likely to bear a key structural role in support of channel activity.

scholarly journals Apolipoprotein E increases the fibrillogenic potential of synthetic peptides derived from Alzheimer's, Gelsolin and AA amyloids

FEBS Letters ◽  
1995 ◽  
Vol 371 (2) ◽  
pp. 110-114 ◽  
Author(s):  
Claudio Soto ◽  
Eduardo M. Castaño ◽  
Frances Prelli ◽  
R. Asok Kumar ◽  
Marc Baumann
Keyword(s):  
Apolipoprotein E ◽  
Synthetic Peptides

scholarly journals Structural features of synthetic peptides of apolipoprotein E that bind the LDL receptor

1995 ◽  
Vol 36 (1) ◽  
pp. 80-88
Author(s):  
C A Dyer ◽  
D P Cistola ◽  
G C Parry ◽  
L K Curtiss
Keyword(s):  
Apolipoprotein E ◽  
Synthetic Peptides ◽  
Ldl Receptor ◽  
Structural Features

scholarly journals Modulation of type-1 protein phosphatase by synthetic peptides corresponding to the carboxyl terminus

FEBS Letters ◽  
1991 ◽  
Vol 285 (1) ◽  
pp. 6-10 ◽  
Author(s):  
Bruce L. Martin ◽  
Carol L. Shriner ◽  
David L. Brautigan
Keyword(s):  
Protein Phosphatase ◽  
Synthetic Peptides ◽  
Carboxyl Terminus
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