The High Molecular Mass, Glycoprotein Ib-Binding Protein Flavocetin-A Induces Only Small Platelet Aggregates in Vitro

2000 ◽  
Vol 97 (2) ◽  
pp. 69-75 ◽  
Author(s):  
Yuta Taniuchi ◽  
Tomihisa Kawasaki ◽  
Yoshihiro Fujimura
Keyword(s):  
Molecular Mass ◽  
Binding Protein ◽  
High Molecular Mass ◽  
Glycoprotein Ib ◽  
Platelet Aggregates ◽  
Small Platelet

scholarly journals Identification of Proteins from Plasmodium falciparum That Are Homologous to Reticulocyte Binding Proteins inPlasmodium vivax

2001 ◽  
Vol 69 (2) ◽  
pp. 1084-1092 ◽  
Author(s):  
Tony Triglia ◽  
Jenny Thompson ◽  
Sonia R. Caruana ◽  
Mauro Delorenzi ◽  
Terry Speed ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Molecular Mass ◽  
Blood Cells ◽  
Potential Role ◽  
High Molecular Mass ◽  
In Vitro Growth ◽  
Merozoite Invasion ◽  
Genome Databases

ABSTRACT Plasmodium falciparum infections can be fatal, whileP. vivax infections usually are not. A possible factor involved in the greater virulence of P. falciparum is that this parasite grows in red blood cells (RBCs) of all maturities whereasP. vivax is restricted to growth in reticulocytes, which represent only approximately 1% of total RBCs in the periphery. Two proteins, expressed at the apical end of the invasive merozoite stage from P. vivax, have been implicated in the targeting of reticulocytes for invasion by this parasite. A search of the P. falciparum genome databases has identified genes that are homologous to the P. vivax rbp-1 and -2 genes. Two of these genes are virtually identical over a large region of the 5′ end but are highly divergent at the 3′ end. They encode high-molecular-mass proteins of >300 kDa that are expressed in late schizonts and localized to the apical end of the merozoite. To test a potential role in merozoite invasion of RBCs, we analyzed the ability of these proteins to bind to mature RBCs and reticulocytes. No binding to mature RBCs or cell preparations enriched for reticulocytes was detected. We identified a parasite clone that lacks the gene for one of these proteins, showing that the gene is not required for normal in vitro growth. Antibodies to these proteins can inhibit merozoite invasion of RBCs.

scholarly journals Expression and characterization of a recombinant C4b-binding protein lacking the β-chain

1995 ◽  
Vol 308 (3) ◽  
pp. 795-800 ◽  
Author(s):  
Y Härdig ◽  
P García de Frutos ◽  
B Dahlbäck
Keyword(s):  
Molecular Mass ◽  
Binding Protein ◽  
Expression System ◽  
Activated Protein C ◽  
Protein S ◽  
High Molecular Mass ◽  
Eukaryotic Expression ◽  
Beta Chain ◽  
Factor I ◽  
Dependent Protein

C4b-binding protein (C4BP) is a high-molecular-mass glycoprotein which contains binding sites for complement component C4b, anti-coagulant vitamin K-dependent protein S and serum amyloid P component (SAP). The major form of C4BP in plasma is composed of seven identical alpha-chains and a single beta-chain. We have expressed full-length cDNA for the alpha-chain in a eukaryotic expression system and characterized functional properties of non-beta-chain-containing C4BP. During synthesis, recombinant alpha-chains polymerized into two different high-molecular-mass C4BP forms which were composed of seven or eight alpha-chains. Recombinant C4BP bound C4(H2O) (used instead of C4b) equally as well as native C4BP, functioned equally as well as factor I cofactor in the degradation of C4(H2O) and bound to SAP. In contrast, the recombinant C4BP did not bind protein S and therefore did not inhibit the ability of protein S to function as a cofactor to activated protein C. Tunicamycin treatment of the transfected cells prevented N-linked glycosylation, but did not affect polymerization of the alpha-chains into a high-molecular-mass C4BP. The non-glycosylated C4BP had comparable properties to glycosylated C4BP in several functional assays. These results demonstrate polymerization of C4BP alpha-chains to be independent both of the beta-chain and of the N-linked carbohydrates. Moreover, N-linked carbohydrates and the beta-chain were neither required for the ability of C4BP to bind C4b and to function as factor I cofactor nor for the interaction with SAP.

Antigenic and genetic characterization of a putative hybrid transferrin-binding protein B fromNeisseria meningitidis

1999 ◽  
Vol 45 (12) ◽  
pp. 1050-1054
Author(s):  
Tamara Menéndez ◽  
Mairet Pérez ◽  
Anabel Alvarez
Keyword(s):  
Neisseria Meningitidis ◽  
Molecular Mass ◽  
Reference Strain ◽  
Binding Protein ◽  
High Molecular Mass ◽  
Putative Hybrid ◽  
Family Strain ◽  
Transferrin Binding Proteins ◽  
Meningococcal Strain

The transferrin-binding protein Bs (TbpBs) from the bacterium Neisseria meningitidis have been divided into two families according to genetic and antigenic features. TbpB from meningococcal strain B385 showed a molecular mass similar to that exhibited by TbpBs belonging to the high molecular mass family of TbpBs. TbpB was recognized by immunoassay using a specific serum directed against the TbpB of the reference strain for this family (strain M982). It was also recognized by a serum elicited against the TbpB of the reference strain for the low molecular mass family (strain B16B6). The tbpB gene from strain B385 was cloned and sequenced. The highest degree of sequence homology was found to be with the TbpBs belonging to the high molecular mass family, although a region of 14 amino acids that is only present in the TbpB from strain B16B6 was also found. This report illustrates a TbpB that shows hybrid antigenic and genetic behaviour.Key words: Neisseria meningitidis, transferrin-binding proteins, TbpB families.

scholarly journals Bombyx mori Nucleopolyhedrovirus Encodes a DNA-Binding Protein Capable of Destabilizing Duplex DNA

1998 ◽  
Vol 72 (4) ◽  
pp. 3107-3116 ◽  
Author(s):  
Victor S. Mikhailov ◽  
Alla L. Mikhailova ◽  
Masashi Iwanaga ◽  
Sumiko Gomi ◽  
Susumu Maeda
Keyword(s):  
Dna Binding ◽  
Molecular Mass ◽  
Bombyx Mori ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Amino Acid Sequences ◽  
Single Stranded Dna ◽  
Calculated Molecular Mass ◽  
Reading Frame

ABSTRACT A DNA-binding protein (designated DBP) with an apparent molecular mass of 38 kDa was purified to homogeneity from BmN cells (derived fromBombyx mori) infected with the B. morinucleopolyhedrovirus (BmNPV). Six peptides obtained after digestion of the isolated protein with Achromobacter protease I were partially or completely sequenced. The determined amino acid sequences indicated that DBP was encoded by an open reading frame (ORF16) located at nucleotides (nt) 16189 to 17139 in the BmNPV genome (GenBank accession no. L33180 ). This ORF (designated dbp) is a homolog of Autographa californica multicapsid NPV ORF25, whose product has not been identified. BmNPV DBP is predicted to contain 317 amino acids (calculated molecular mass of 36.7 kDa) and to have an isoelectric point of 7.8. DBP showed a tendency to multimerization in the course of purification and was found to bind preferentially to single-stranded DNA. When bound to oligonucleotides, DBP protected them from hydrolysis by phage T4 DNA polymerase-associated 3′→5′ exonuclease. The sizes of the protected fragments indicated that a binding site size for DBP is about 30 nt per protein monomer. DBP, but not BmNPV LEF-3, was capable of unwinding partial DNA duplexes in an in vitro system. This helix-destabilizing ability is consistent with the prediction that DBP functions as a single-stranded DNA binding protein in virus replication.

Sign in / Sign up

Export Citation Format

Share Document