Structure and Expression of the Gene Encoding Murine M-Protein, a Sarcomere-Specific Member of the Immunoglobulin Superfamily

Genomics ◽  
1998 ◽  
Vol 49 (1) ◽  
pp. 83-95 ◽  
Author(s):  
Frank Steiner ◽  
Klaus Weber ◽  
Dieter O. Fürst
Keyword(s):  
Protein A ◽  
M Protein ◽  
Immunoglobulin Superfamily ◽  
Gene Encoding

Molecular characterization of three mutations in katG affecting the activity of hydroperoxidase I of Escherichia coli

1990 ◽  
Vol 68 (7-8) ◽  
pp. 1037-1044 ◽  
Author(s):  
Peter C. Loewen ◽  
Jacek Switala ◽  
Mark Smolenski ◽  
Barbara L. Triggs-Raine
Keyword(s):  
Escherichia Coli ◽  
Specific Activity ◽  
Polymerase Chain Reaction Amplification ◽  
Protein A ◽  
Wild Type ◽  
Wild Type Enzyme ◽  
Gene Encoding ◽  
Reaction Amplification ◽  
Mutant Genes

Hydroperoxidase I (HPI) of Escherichia coli is a bifunctional enzyme exhibiting both catalase and peroxidase activities. Mutants lacking appreciable HPI have been generated using nitrosoguanidine and the gene encoding HPI, katG, has been cloned from three of these mutants using either classical probing methods or polymerase chain reaction amplification. The mutant genes were sequenced and the changes from wild-type sequence identified. Two mutants contained G to A changes in the coding strand, resulting in glycine to aspartate changes at residues 119 (katG15) and 314 (katG16) in the deduced amino acid sequence of the protein. A third mutant contained a C to T change resulting in a leucine to phenylalanine change at residue 139 (katG14). The Phe139-, Asp119-, and Asp314-containing mutants exhibited 13, < 1, and 18%, respectively, of the wild-type catalase specific activity and 43, 4, and 45% of the wild-type peroxidase specific activity. All mutant enzymes bound less protoheme IX than the wild-type enzyme. The sensitivities of the mutant enzymes to the inhibitors hydroxylamine, azide, and cyanide and the activators imidazole and Tris were similar to those of the wild-type enzyme. The mutant enzymes were more sensitive to high temperature and to β-mercaptoethanol than the wild-type enzyme. The pH profiles of the mutant catalases were unchanged from the wild-type enzyme.Key words: catalase, hydroperoxidase I, mutants, sequence analysis.

scholarly journals Overproduction of SecA Suppresses the Export Defect Caused by a Mutation in the Gene Encoding the Escherichia coli Export Chaperone SecB

1999 ◽  
Vol 181 (10) ◽  
pp. 3010-3017 ◽  
Author(s):  
Heather A. Cook ◽  
Carol A. Kumamoto
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane Proteins ◽  
Protein A ◽  
In Vivo Studies ◽  
Wild Type ◽  
Gene Encoding ◽  
Precursor Proteins ◽  
Additional Support ◽  
Insight Into

ABSTRACT SecB is a cytosolic protein required for rapid and efficient export of particular periplasmic and outer membrane proteins inEscherichia coli. SecB promotes export by stabilizing newly synthesized precursor proteins in a nonnative conformation and by targeting the precursors to the inner membrane. Biochemical studies suggest that SecB facilitates precursor targeting by binding to the SecA protein, a component of the membrane-embedded translocation apparatus. To gain more insight into the functional interaction of SecB and SecA, in vivo, mutations in the secA locus that compensate for the export defect caused by the secBmissense mutation secBL75Q were isolated. Two suppressors were isolated, both of which led to the overproduction of wild-type SecA protein. In vivo studies demonstrated that the SecBL75Q mutant protein releases precursor proteins at a lower rate than does wild-type SecB. Increasing the level of SecA protein in the cell was found to reverse this slow-release defect, indicating that overproduction of SecA stimulates the turnover of SecBL75Q-precursor complexes. These findings lend additional support to the proposed pathway for precursor targeting in which SecB promotes targeting to the translocation apparatus by binding to the SecA protein.

scholarly journals Host Pathways of Hemostasis that Regulate Group A Streptococcus pyogenes Pathogenicity

2020 ◽  
Vol 21 (2) ◽  
pp. 193-201
Author(s):  
Victoria A. Ploplis ◽  
Francis J. Castellino
Keyword(s):  
Streptococcus Pyogenes ◽  
Inflammatory Responses ◽  
Group A Streptococcus ◽  
Protein A ◽  
M Protein ◽  
Severe Group ◽  
Group A ◽  
Flow Through ◽  
Hallmark Feature ◽  
Major Target

A hallmark feature of severe Group A Streptococcus pyogenes (GAS) infection is dysregulated hemostasis. Hemostasis is the primary pathway for regulating blood flow through events that contribute towards clot formation and its dissolution. However, a number of studies have identified components of hemostasis in regulating survival and dissemination of GAS. Several proteins have been identified on the surface of GAS and they serve to either facilitate invasion to host distal sites or regulate inflammatory responses to the pathogen. GAS M-protein, a surface-exposed virulence factor, appears to be a major target for interactions with host hemostasis proteins. These interactions mediate biochemical events both on the surface of GAS and in the solution when M-protein is released into the surrounding environment through shedding or regulated proteolytic processes that dictate the fate of this pathogen. A thorough understanding of the mechanisms associated with these interactions could lead to novel approaches for altering the course of GAS pathogenicity.

scholarly journals teiresias, a Fruitless target gene encoding an immunoglobulin-superfamily transmembrane protein, is required for neuronal feminization in Drosophila

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Kosei Sato ◽  
Hiroki Ito ◽  
Daisuke Yamamoto
Keyword(s):  
Transmembrane Protein ◽  
Immunoglobulin Superfamily ◽  
Gene Encoding ◽  
Sexual Dimorphisms ◽  
Sensory Axons ◽  
Midline Crossing ◽  
Genome Wide ◽  
Genome Wide Search ◽  
Mrna And Protein Expression ◽  
Male Specific

Abstract This study aims at identifying transcriptional targets of FruitlessBM (FruBM), which represents the major isoform of male-specific FruM transcription factors that induce neural sexual dimorphisms. A promoter of the axon-guidance factor gene robo1 carries the 16-bp palindrome motif Pal1, to which FruM binds. Our genome-wide search for Pal1-homologous sequences yielded ~200 candidate genes. Among these, CG17716 potentially encodes a transmembrane protein with extracellular immunoglobulin (Ig)-like domains similar to Robo1. Indeed, FruBM overexpression reduced CG17716 mRNA and protein expression. In the fru-expressing mAL neuron cluster exhibiting sexual dimorphism, we found that CG17716 knockdown in female neurons completely transformed all neurites to the male-type. Conversely, CG17716 overexpression suppressed male-specific midline crossing of fru-expressing sensory axons. We renamed CG17716 teiresias (tei) based on this feminizing function. We hypothesize that Tei interacts with other Ig superfamily transmembrane proteins, including Robo1, to feminize the neurite patterns in females, whereas FruBM represses tei transcription in males.

scholarly journals Raised ?2-Microglobulin as a Surrogate Marker in Non-Secretory Multiple Myeloma

2017 ◽  
Vol 16 (1) ◽  
pp. 142-145
Author(s):  
Bimal K Agrawal ◽  
Anshul Sehgal ◽  
Vikas Deswal ◽  
Prem Singh ◽  
Usha Agrawal
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Rare Case ◽  
Plasma Cells ◽  
Medical Science ◽  
Protein A ◽  
Surrogate Marker ◽  
M Protein ◽  
Review Of Literature ◽  
Lytic Lesions

Multiple myeloma is a neoplasm of plasma cells in the bone marrow. It is characterised by lytic lesions in the bones, marrow plasmacytosis and presence of M protein in serum and/or urine. Serum ?2 microglobulin is also raised and can be used for classification and prognostication of the disease. In the absence of M protein, the disease is known as non-secretory myeloma. It is proposed that raised ?2 microglobulin can be used for diagnosis and therapeutic guidance in the absence of M protein. A rare case of nonsecretory myeloma with neurocognitive impairment along with review of literature is being presented. The patient had multiple lytic lesions in bones with marked increase in plasma cells in bone marrow. M protein was not detectable in serum or urine but serum ?2 microglobulin was much elevated.Bangladesh Journal of Medical Science Vol.16(1) 2017 p.142-145

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.

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