Synthesis of the amino-terminal decapeptide of human calcitonin, in which the disulfide bond is replaced by a thioether group

1980 ◽  
Vol 45 (4) ◽  
pp. 1305-1314 ◽  
Author(s):  
Zdenko Procházka ◽  
Karel Jošt
Keyword(s):  
Disulfide Bond ◽  
Human Calcitonin ◽  
Amino Terminal ◽  
Active Ester ◽  
Stepwise Method ◽  
Group A

A fully protected amino-terminal decapeptide Ib with the sequence of human calcitonin, in which the S-S bridge was replaced by the S-CH2 group (a so-called 7-carba-analogue), was synthetized mainly by the stepwise method. The cyclization of the linear decapeptide was performed by means of active ester.

scholarly journals Conversion of an M- group A streptococcus to M+ by transfer of a plasmid containing an M6 gene.

1986 ◽  
Vol 164 (5) ◽  
pp. 1641-1651 ◽  
Author(s):  
J R Scott ◽  
P C Guenthner ◽  
L M Malone ◽  
V A Fischetti
Keyword(s):  
Structural Gene ◽  
Human Blood ◽  
Group A Streptococcus ◽  
M Protein ◽  
Gene Encoding ◽  
Hyperimmune Serum ◽  
Amino Terminal ◽  
Group A ◽  
Hyperimmune Rabbit ◽  
Streptococcal Strain

An M28-derived group A streptococcal strain deleted for the gene encoding M protein was converted to M+ by introduction of a plasmid carrying emm6, the structural gene for type 6 M protein from strain D471. The reconstituted M+ strain, JRS2, resists phagocytosis in human blood and is opsonized by anti-M6 hyperimmune serum, but not by anti-M28 serum. Immunofluorescent microscopy and ELISA demonstrate the presence of M protein on its surface. In addition, JRS2 removes opsonic antibodies from hyperimmune rabbit sera generated by immunization with purified ColiM6 protein and with a synthetic amino-terminal peptide derived from M6. Immunization of rabbits with JRS2 generates opsonic anti-M6 antibodies. These results indicate that the cloned emm6 gene contains the information necessary to convert a phagocytosis-sensitive streptococcus to phagocytosis resistance. Furthermore, it also contains the determinants for M type specificity and those required to elicit opsonic antibodies. It thus appears to determine all the traits associated with M protein.

scholarly journals IgA proteases of two distinct specificities are released by Neisseria meningitidis.

1980 ◽  
Vol 152 (5) ◽  
pp. 1442-1447 ◽  
Author(s):  
M H Mulks ◽  
A G Plaut ◽  
H A Feldman ◽  
B Frangione
Keyword(s):  
Amino Acid ◽  
Neisseria Meningitidis ◽  
Heavy Chain ◽  
Peptide Bond ◽  
Amino Acid Sequences ◽  
Hinge Region ◽  
Amino Terminal ◽  
Group A

Strains of Neisseria meningitidis produce two distinct extracellular IgA proteases that cleave the human IgA1 heavy chain at different points within the hinge region. Type 1 protease cleaves the prolyl-seryl peptide bond at position 237-238; type type 2 protease cleaves the prolyl-threonyl bond two residues amino terminal to that bond attacked by type 1 enzyme. Each meningococcal isolate elaborates only one of these two enzymes, and the type of protease produced correlates with certain serogroups: group A yielding only type 1, and groups X and Y only type 2 enzyme. In addition, analysis of amino acid sequences of human alpha-chain proteins reveals that the repeating octapeptide characteristic of the IgA1 hinge region is actually triplicated.

Effects of disulfide bond and cholesterol derivatives on human calcitonin amyloid formation

Biopolymers ◽  
2019 ◽  
Vol 111 (5) ◽  
Author(s):  
Richard Lantz ◽  
Brian Busbee ◽  
Ewa P. Wojcikiewicz ◽  
Deguo Du
Keyword(s):  
Disulfide Bond ◽  
Human Calcitonin ◽  
Amyloid Formation

scholarly journals Periplasmic Transit and Disulfide Bond Formation of the Autotransported Shigella Protein IcsA

2001 ◽  
Vol 183 (3) ◽  
pp. 951-958 ◽  
Author(s):  
Lauren D. Brandon ◽  
Marcia B. Goldberg
Keyword(s):  
Outer Membrane ◽  
Disulfide Bond ◽  
Bond Formation ◽  
Surface Expression ◽  
Proteinase K ◽  
Disulfide Bond Formation ◽  
Amino Terminal ◽  
Intracellular Movement ◽  
Carboxy Terminal ◽  
Type V

ABSTRACT The Shigella outer membrane protein IcsA belongs to the family of type V secreted (autotransported) virulence factors. Members of this family mediate their own translocation across the bacterial outer membrane: the carboxy-terminal β domain forms a β barrel channel in the outer membrane through which the amino-terminal α domain passes. IcsA, which is localized at one pole of the bacterium, mediates actin assembly by Shigella, which is essential for bacterial intracellular movement and intercellular dissemination. Here, we characterize the transit of IcsA across the periplasm during its secretion. We show that an insertion in the dsbB gene, whose gene product mediates disulfide bond formation of many periplasmic intermediates, does not affect the surface expression or unipolar targeting of IcsA. However, IcsA forms one disulfide bond in the periplasm in a DsbA/DsbB-dependent fashion. Furthermore, cellular fractionation studies reveal that IcsA has a transient soluble periplasmic intermediate. Our data also suggest that IcsA is folded in a proteinase K-resistant state in the periplasm. From these data, we propose a novel model for the secretion of IcsA that may be applicable to other autotransported proteins.

scholarly journals Effects of Different Hemodialysis Treatments on Abnormal Mineral and Bone Metabolism in Patients with Chronic Renal Failure

2020 ◽  
Vol 4 (6) ◽  
Author(s):  
Qiang Li
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Bone Metabolism ◽  
Type I ◽  
High Flux ◽  
Blood Calcium ◽  
Amino Terminal ◽  
Group A ◽  
The Difference ◽  
Group B

Objective: To investigate the effects of different hemodialysis treatments on abnormal mineral and bone metabolism in patients with chronic renal failure. Methods: A random number table was used to divide 80 patients with chronic renal failure admitted to our hospital from January 2018 to January 2019 into 2 groups, with 40 cases in each group. Group A was treated with low-flux hemodialysis, and group B was treated with high-flux hemodialysis. The related indicators of mineral and bone metabolism of the two groups were compared. Results: Before treatment, the blood calcium, blood phosphorus, intact parathyroid hormone (iPTH), type I procollagen amino terminal peptide (PINP), fibroblast growth factor 23 (FGF23), serum creatinine (Scr) indicators of the two groups were compared. The difference was not statistically significant(P>0.05); After treatment, the blood calcium levels of the two groups were higher than before treatment, the blood phosphorus, iPTH, PINP, FGF23, and Scr levels were lower than before treatment, and the blood calcium level of group B was higher than that of group A, while blood phosphorus, iPTH, PINP, FGF23, and Scr levels were lower than group A, the difference was statistically significant (P<0.05). Conclusion: Compared with low-flux hemodialysis, patients with chronic renal failure treated with high-flux hemodialysis have better results, which can correct abnormal bone metabolism and improve Scr levels.

scholarly journals Multivalent Group A Streptococcal Vaccine Elicits Bactericidal Antibodies against Variant M Subtypes

2005 ◽  
Vol 12 (7) ◽  
pp. 833-836 ◽  
Author(s):  
James B. Dale ◽  
Thomas Penfound ◽  
Edna Y. Chiang ◽  
Valerie Long ◽  
Stanford T. Shulman ◽  
...  
Keyword(s):  
Wide Spectrum ◽  
Epidemiologic Studies ◽  
M Protein ◽  
Group A Streptococci ◽  
Protein Vaccine ◽  
Amino Terminal ◽  
M Proteins ◽  
Group A ◽  
Clinical Illness

ABSTRACT Group A streptococci cause a wide spectrum of clinical illness. One of several strategies for vaccine prevention of these infections is based on the type-specific M protein epitopes. A multivalent M protein-based vaccine containing type-specific determinants from 26 different M serotypes is now in clinical trials. Recent epidemiologic studies have shown that, within some serotypes, the amino-terminal M protein sequence may show natural variation, giving rise to subtypes. This raises the possibility that vaccine-induced antibodies against the parent type may not be as effective in promoting bactericidal killing of variant subtypes. In the present study we used rabbit antisera against the 26-valent M protein-based vaccine in bactericidal tests against M1, M3, and M5 streptococci, which were represented by multiple subtypes. We show that the vaccine antibodies effectively promoted in vitro bactericidal activity despite the fact that the M proteins contained naturally occurring variant sequences in the regions corresponding to the vaccine sequence. Our results show that the variant M proteins generally do not result in significant differences in opsonization promoted by rabbit antisera raised against the 26-valent vaccine, suggesting that a multivalent M protein vaccine may not permit variant subtypes of group A streptococci to escape in a highly immunized population.

scholarly journals The importance of the location of antibody binding on the M6 protein for opsonization and phagocytosis of group A M6 streptococci.

1988 ◽  
Vol 167 (3) ◽  
pp. 1114-1123 ◽  
Author(s):  
K F Jones ◽  
V A Fischetti
Keyword(s):  
Complement Fixation ◽  
Hypervariable Region ◽  
Antibody Binding ◽  
Factor H ◽  
Complement Factor ◽  
Amino Terminal ◽  
Group A ◽  
Native Group ◽  
Binding Titer

One of 19 mAbs against the native group A streptococcal M6 protein proved opsonic for type 6 organisms in a bactericidal assay. The opsonic and three nonopsonic antibodies were selected for isotype and complement fixation studies based on previous knowledge of their epitope site on the M6 molecule. While mAb 3B8 (IgG3), whose epitope is in the NH2-terminal hypervariable region of the molecule (distal from the cell), and mAbs 10B6 (IgG2a) and 10F5 (IgG2b), both located in the conserved central region of the molecule, all fix complement, 10A11 (IgG1) did not. Only mAb 3B8 was opsonic despite the fact that mAbs 10B6 and 10F5 both exhibited similar complement-fixing capacity, binding titer, and surface exposure of epitopes. Analysis of antibodies raised against synthetic peptides representing various regions of the M6 protein showed that only the amino-terminal peptide (residues 1-21) was capable of eliciting opsonic antibodies, despite the fact that peptides from other areas produced antibodies with high-binding titers to the native M6 protein and also with the ability to bind to intact streptococcal cells. These results not only support the observed type specificity of opsonic antibodies, but also clearly point to the importance of the location of antibody binding on the M molecule relative to the actual functional capacity of the antibody with respect to the opsonization and phagocytosis of M6 streptococci. These results may underscore the recently observed role of complement Factor H in the antiphagocytic activity of the M protein.

scholarly journals Two Distinct Genotypes of prtF2, Encoding a Fibronectin Binding Protein, and Evolution of the Gene Family in Streptococcus pyogenes

2004 ◽  
Vol 186 (22) ◽  
pp. 7601-7609 ◽  
Author(s):  
V. Ramachandran ◽  
J. D. McArthur ◽  
C. E. Behm ◽  
C. Gutzeit ◽  
M. Dowton ◽  
...  
Keyword(s):  
Dna Sequences ◽  
T Antigen ◽  
Host Cells ◽  
Amino Terminal ◽  
Selective Pressures ◽  
Wide Range ◽  
Group A ◽  
Fibronectin Binding Protein ◽  
Recent Origin ◽  
Fibronectin Binding

ABSTRACT The group A Streptococcus (GAS) is an important pathogen that is responsible for a wide range of human diseases. Fibronectin binding proteins (FBPs) play an important role in promoting GAS adherence and invasion of host cells. The prtF2 gene encodes an FBP and is present in approximately 60% of GAS strains. In the present study we examined 51 prtF2-positive GAS strains isolated from the Northern Territory of Australia, and here we describe two genotypes of prtF2 which are mutually exclusive. The two genotypes have been identified previously as pfbp and fbaB. We show that these genotypes map to the same chromosomal location within the highly recombinatorial fibronectin-collagen-T antigen (FCT) locus, indicating that they arose from a common ancestor, and in this study these genotypes were designated the pfbp type and the fbaB type. Phylogenetic analysis of seven pfbp types, 14 fbaB types, and 11 prtF2-negative GAS strains by pulsed-field gel electrophoresis (PFGE) produced 32 distinct PFGE patterns. Interpretation of evolution based on the PFGE dendrogram by parsimony suggested that the pfbp type had a recent origin compared to the fbaB type. A comparison of multiple DNA sequences of the pfbp and fbaB types revealed a mosaic pattern for the amino-terminal region of the pfbp types. The fbaB type is generally conserved at the amino terminus but varies in the number of fibronectin binding repeats in the carboxy terminus. Our data also suggest that there is a possible association of the pfbp genotype with sof (84.2%), while the fbaB genotype was found in a majority of the GAS strains negative for sof (90.6%), indicating that these two prtF2 subtypes may be under different selective pressures.

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