scholarly journals Impact of the SpeB Protease on Binding of the Complement Regulatory Proteins Factor H and Factor H-Like Protein 1 by Streptococcus pyogenes

2005 ◽  
Vol 73 (4) ◽  
pp. 2040-2050 ◽  
Author(s):  
Lin Wei ◽  
Vinod Pandiripally ◽  
Eugene Gregory ◽  
Micaya Clymer ◽  
David Cue
Keyword(s):  
Binding Site ◽  
Streptococcus Pyogenes ◽  
Dna Sequences ◽  
Factor H ◽  
Regulatory Proteins ◽  
Microbial Pathogens ◽  
Complement Regulatory Proteins ◽  
Human Pathogenic Bacterium ◽  
Binding Factor ◽  
Intracellular Invasion

ABSTRACT Microbial pathogens often exploit human complement regulatory proteins such as factor H (FH) and factor H-like protein 1 (FHL-1) for immune evasion. Fba is an FH and FHL-1 binding protein expressed on the surface of the human pathogenic bacterium Streptococcus pyogenes, a common agent of pharyngeal, skin, and soft-tissue infections. Fba has been shown to contribute to phagocytosis resistance, intracellular invasion, and virulence in mice. Here, we look at the role of Fba in recruitment of FH and FHL-1 by five serotype M1 isolates of streptococci. Inactivation of fba greatly inhibited binding of FH and FHL-1 by all isolates, indicating that Fba is a major FH and FHL-1 binding factor of serotype M1 streptococci. For three isolates, FH binding was significantly reduced in stationary-phase cultures and correlated with high levels of protease activity and SpeB (an extracellular cysteine protease) protein in culture supernatants. Analysis of a speB mutant confirmed that SpeB accounts for the loss of Fba from the cell surface, suggesting that the protease may modulate FH and FHL-1 recruitment during infection. Comparisons of fba DNA sequences revealed that the FH and FHL-1 binding site in Fba is conserved among the M1 isolates. Although the ligand binding site is not strictly conserved in Fba from a serotype M49 isolate, the M49 Fba protein was found to bind both FH and FHL-1. Collectively, these data indicate that binding of FH and FHL-1 is a conserved function of Fba while modulation of Fba function by SpeB is variable.

scholarly journals Putative Coiled-Coil Structural Elements of the BBA68 Protein of Lyme Disease Spirochetes Are Required for Formation of Its Factor H Binding Site

2005 ◽  
Vol 187 (4) ◽  
pp. 1317-1323 ◽  
Author(s):  
John V. McDowell ◽  
Matthew E. Harlin ◽  
Elizabeth A. Rogers ◽  
Richard T. Marconi
Keyword(s):  
Lyme Disease ◽  
Binding Site ◽  
Immune Evasion ◽  
Coiled Coil ◽  
Factor H ◽  
Regulatory Proteins ◽  
Structural Elements ◽  
Binding Ability ◽  
Complement Regulatory Proteins ◽  
Factor I

ABSTRACT Factor H and factor H like-protein 1 (FHL-1) are complement regulatory proteins that serve as cofactors for the factor I-mediated cleavage of C3b. Some Lyme disease and relapsing fever spirochete species bind factor H to their surface to facilitate immune evasion. The Lyme disease spirochetes produce several factor H binding proteins (FHBPs) that form two distinct classes. Class I FHBPs (OspE orthologs and paralogs) bind only factor H, while class II FHBPs (BBA68) bind both factor H and FHL-1. BBA68 belongs to a large paralogous protein family, and of these paralogs, BBA69 is the member most closely related to BBA68. To determine if BBA69 can also bind factor H, recombinant protein was generated and tested for factor H binding. BBA69 did not exhibit factor H binding ability, suggesting that among family 54 paralogs, factor H binding is unique to BBA68. To identify the determinants of BBA68 that are involved in factor H binding, truncation and site-directed mutational analyses were performed. These analyses revealed that the factor H binding site is discontinuous and provide strong evidence that coiled-coil structural elements are involved in the formation of the binding site.

scholarly journals Genetics of HUS: the impact of MCP, CFH, and IF mutations on clinical presentation, response to treatment, and outcome

Blood ◽  
2006 ◽  
Vol 108 (4) ◽  
pp. 1267-1279 ◽  
Author(s):  
Jessica Caprioli ◽  
Marina Noris ◽  
Simona Brioschi ◽  
Gaia Pianetti ◽  
Federica Castelletti ◽  
...  
Keyword(s):  
Disease Recurrence ◽  
Factor H ◽  
Response To Therapy ◽  
Regulatory Proteins ◽  
Response To Treatment ◽  
Complement Factor ◽  
Genetic Studies ◽  
Complement Regulatory Proteins ◽  
Uremic Syndrome ◽  
The Impact

Abstract Hemolytic uremic syndrome (HUS) is a thrombotic microangiopathy with manifestations of hemolytic anemia, thrombocytopenia, and renal impairment. Genetic studies have shown that mutations in complement regulatory proteins predispose to non–Shiga toxin–associated HUS (non-Stx–HUS). We undertook genetic analysis on membrane cofactor protein (MCP), complement factor H (CFH), and factor I (IF) in 156 patients with non-Stx–HUS. Fourteen, 11, and 5 new mutational events were found in MCP, CFH, and IF, respectively. Mutation frequencies were 12.8%, 30.1%, and 4.5% for MCP, CFH, and IF, respectively. MCP mutations resulted in either reduced protein expression or impaired C3b binding capability. MCP-mutated patients had a better prognosis than CFH-mutated and nonmutated patients. In MCP-mutated patients, plasma treatment did not impact the outcome significantly: remission was achieved in around 90% of both plasma-treated and plasma-untreated acute episodes. Kidney transplantation outcome was favorable in patients with MCP mutations, whereas the outcome was poor in patients with CFH and IF mutations due to disease recurrence. This study documents that the presentation, the response to therapy, and the outcome of the disease are influenced by the genotype. Hopefully this will translate into improved management and therapy of patients and will provide the way to design tailored treatments.

scholarly journals SiteOut: an online tool to design binding site-free DNA sequences

2015 ◽  
Author(s):  
Javier Estrada ◽  
Teresa Ruiz-Herrero ◽  
Clarissa Scholes ◽  
Zeba Wunderlich ◽  
Angela DePace
Keyword(s):  
Binding Site ◽  
Dna Sequences ◽  
Binding Sites ◽  
Regulatory Proteins ◽  
Biological Processes ◽  
Major Goal ◽  
Specific Sequence ◽  
Online Tool ◽  
Protein Binding Sites ◽  
Regulatory Dna

DNA-binding proteins control many fundamental biological processes such as transcription, recombination and replication. A major goal is to decipher the role that DNA sequence plays in orchestrating the binding and activity of such regulatory proteins. To address this goal, it is useful to rationally design DNA sequences with desired numbers, affinities and arrangements of protein binding sites. However, removing binding sites from DNA is computationally non-trivial since one risks creating new sites in the process of deleting or moving others. Here we present an online binding site removal tool, SiteOut, that enables users to design arbitrary DNA sequences that entirely lack binding sites for factors of interest. SiteOut can also be used to delete sites from a specific sequence, or to introduce site-free spacers between functional sequences without creating new sites at the junctions. In combination with commercial DNA synthesis services, SiteOut provides a powerful and flexible platform for synthetic projects that interrogate regulatory DNA. Here we describe the algorithm and illustrate the ways in which SiteOut can be used; it is publicly available at https://depace.med.harvard.edu/siteout/

scholarly journals An imbalance of human complement regulatory proteins CFHR1, CFHR3 and factor H influences risk for age-related macular degeneration (AMD)

2010 ◽  
Vol 19 (23) ◽  
pp. 4694-4704 ◽  
Author(s):  
Lars G. Fritsche ◽  
Nadine Lauer ◽  
Andrea Hartmann ◽  
Selina Stippa ◽  
Claudia N. Keilhauer ◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Factor H ◽  
Age Related Macular Degeneration ◽  
Regulatory Proteins ◽  
Human Complement ◽  
Complement Regulatory Proteins ◽  
Age Related

scholarly journals Two human antibodies to a meningococcal serogroup B vaccine antigen enhance binding of complement Factor H by stabilizing the Factor H binding site

2021 ◽  
Vol 17 (6) ◽  
pp. e1009655
Author(s):  
Nathaniel A. Sands ◽  
Peter T. Beernink
Keyword(s):  
Binding Site ◽  
Human Subjects ◽  
Bacterial Pathogen ◽  
Factor H ◽  
Microbial Pathogens ◽  
Vaccine Antigen ◽  
Complement Factor ◽  
Amino Terminal ◽  
Minimal Contact ◽  
Amino Terminal Domain

Microbial pathogens bind host complement regulatory proteins to evade the immune system. The bacterial pathogen Neisseria meningitidis, or meningococcus, binds several complement regulators, including human Factor H (FH). FH binding protein (FHbp) is a component of two licensed meningococcal vaccines and in mice FHbp elicits antibodies that inhibit binding of FH to FHbp, which defeat the bacterial evasion mechanism. However, humans vaccinated with FHbp develop antibodies that enhance binding of FH to the bacteria, which could limit the effectiveness of the vaccines. In the present study, we show that two vaccine-elicited antibody fragments (Fabs) isolated from different human subjects increase binding of complement FH to meningococcal FHbp by ELISA. The two Fabs have different effects on the kinetics of FH binding to immobilized FHbp as measured by surface plasmon resonance. The 1.7- and 2.0-Å resolution X-ray crystal structures of the Fabs in complexes with FHbp illustrate that the two Fabs bind to similar epitopes on the amino-terminal domain of FHbp, adjacent to the FH binding site. Superposition models of ternary complexes of each Fab with FHbp and FH show that there is likely minimal contact between the Fabs and FH. Collectively, the structures reveal that the Fabs enhance binding of FH to FHbp by altering the conformations and mobilities of two loops adjacent to the FH binding site of FHbp. In addition, the 1.5 Å-resolution structure of one of the isolated Fabs defines the structural rearrangements associated with binding to FHbp. The FH-enhancing human Fabs, which are mirrored in the human polyclonal antibody responses, have important implications for tuning the effectiveness of FHbp-based vaccines.

scholarly journals Acquisition of Regulators of Complement Activation by Streptococcus pyogenes Serotype M1

2002 ◽  
Vol 70 (11) ◽  
pp. 6206-6214 ◽  
Author(s):  
Vinod Pandiripally ◽  
Eugene Gregory ◽  
David Cue
Keyword(s):  
Cell Surface ◽  
Stationary Phase ◽  
Streptococcus Pyogenes ◽  
Complement Activation ◽  
Surface Protein ◽  
Factor H ◽  
Regulatory Proteins ◽  
Cell Surface Expression ◽  
Bacterial Cells ◽  
Regulators Of Complement Activation

ABSTRACT Opsonization of bacteria by complement proteins is an important component of the immune response. The pathogenic bacterium Streptococcus pyogenes has evolved multiple mechanisms for the evasion of complement-mediated opsonization. One mechanism involves the binding of human regulators of complement activation such as factor H (FH) and FH-like protein 1 (FHL-1). Acquisition of these regulatory proteins can limit deposition of the opsonin C3b on bacteria, thus decreasing the pathogen's susceptibility to phagocytosis. Binding of complement regulatory proteins by S. pyogenes has previously been attributed to the streptococcal M and M-like proteins. Here, we report that the S. pyogenes cell surface protein Fba can mediate binding of FH and FHL-1. We constructed mutant derivatives of S. pyogenes that lack Fba, M1 protein, or both proteins and assayed the strains for FH binding, susceptibility to phagocytosis, and C3 deposition. Fba expression was found to be sufficient for binding of purified FH as well as for binding of FH and FHL-1 from human plasma. Plasma adsorption experiments also revealed that M1+ Fba+ streptococci preferentially bind FHL-1, whereas M1− Fba+ streptococci have similar affinities for FH and FHL-1. Fba was found to contribute to the survival of streptococci incubated with human blood and to inhibit C3 deposition on bacterial cells. Streptococci harvested from log-phase cultures readily bound FH, but binding was greatly reduced for bacteria obtained from stationary-phase cultures. Bacteria cultured in the presence of the protease inhibitor E64 maintained FH binding activity in stationary phase, suggesting that Fba is removed from the cell surface via proteolysis. Western analyses confirmed that E64 stabilizes cell surface expression of Fba. These data indicate that Fba is an antiopsonic, antiphagocytic protein that may be regulated by cell surface proteolysis.

scholarly journals Cloning and characterization of a cDNA representing a putative complement-regulatory plasma protein from barred sand bass (Parablax neblifer)

1994 ◽  
Vol 301 (2) ◽  
pp. 391-397 ◽  
Author(s):  
A Dahmen ◽  
T Kaidoh ◽  
P F Zipfel ◽  
I Gigli
Keyword(s):  
Plasma Protein ◽  
Regulatory Protein ◽  
Structural Similarity ◽  
Factor H ◽  
Regulatory Proteins ◽  
Expression Library ◽  
Reading Frame ◽  
Complement Regulatory Proteins ◽  
Specific Protease ◽  
Calculated Mass

It has been demonstrated previously that plasma from a number of vertebrate species including the phylogenetically old barred sand bass possesses molecules that cleave the alpha'-chain of the activated third (C3b) and fourth (C4b) components of the human complement system. A specific protease and a cofactor protein were identified to be responsible for this cleavage. The cofactor activity in sand bass correlated with a 110 kDa polypeptide chain of a 360 kDa plasma protein. The evolutionary conservation was probed at the cDNA level and subsequently a cDNA clone of barred sand bass was isolated that represents a protein with structural similarity to mammalian complement-regulatory proteins. The cDNA (SB1) was identified by immunoscreening of a sand bass liver expression library using affinity-purified IgG antibodies raised against the isolated 110 kDa material. The cDNA is 3397 bp in size and the open reading frame represents a protein of 1053 amino acid residues with a hydrophobic signal peptide indicative of a secreted protein. The calculated mass of the mature protein (SBP1) is 115.2 kDa which is in good agreement with the molecular mass of 110 kDa determined for the sand bass serum protein. Similarly to mammalian complement-regulatory proteins, the protein deduced from the sand bass cDNA is organized into short consensus repeats (SCR). It consists of 17 SCRs, of which SCRs 2, 12 and 16 exhibit significant homology to SCRs 2, 15 and 19 of human factor H, and SCRs 11, 12 and 13 have homology to SCRs 1, 2 and 3 of human C4b-binding protein. For the first time a complete cDNA representing a putative complement-regulatory protein which is structurally related to mammalian complement proteins has been isolated from a bony fish.

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