scholarly journals Attenuated Expression of the mgaVirulence Regulon in an M Serotype 50 Mouse-Virulent Group A Streptococcal Strain

1999 ◽  
Vol 67 (12) ◽  
pp. 6691-6694 ◽  
Author(s):  
Der-Li Yung ◽  
Kevin S. McIver ◽  
June R. Scott ◽  
Susan K. Hollingshead
Keyword(s):  
Amino Acid ◽  
Gene Product ◽  
Protein Function ◽  
Virulence Genes ◽  
M Protein ◽  
Affect Protein Function ◽  
Group A ◽  
Virulent Group ◽  
Streptococcal Strain

ABSTRACT The attenuated expression of virulence genes found in a group A streptococcal strain that is naturally pathogenic for mice was postulated to result from a defect in the strain's multigene regulator, Mga. The sequence of the mga gene reveals three amino acid changes in the gene product that might affect protein function. The defect in the mga gene was complemented by providing either the closely similar mga4 allele or a more divergent mga1 allele in trans. Complementation increased the amount of emm50 transcript and the quantity of surface-extractable M protein, restoring virulence function.

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 STUDIES OF L FORMS AND PROTOPLASTS OF GROUP A STREPTOCOCCI

1959 ◽  
Vol 110 (6) ◽  
pp. 853-874 ◽  
Author(s):  
Earl H. Freimer ◽  
Richard M. Krause ◽  
Maclyn McCarty
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
M Protein ◽  
Group A Streptococci ◽  
Group A ◽  
Isolated Cell ◽  
Streptococcal Strain

L forms of Group A streptococci have been isolated by the use of penicillin gradient agar plates. Osmotically fragile protoplasts of Group A streptococci have been obtained by the use of Group C phage-associated lysin which lyses Group A streptococci and their isolated cell walls. Membranes surrounding these enzymatically derived protoplasts have been isolated, and chemical and immunological studies indicate that they are free of cell wall carbohydrate and M protein. The streptococcal protoplasts reproduce as colonies which are morphologically indistinguishable from streptococcal L forms. Evidence is presented to show that these two streptococcal derivatives are serologically and physiologically related to each other as well as to the parent streptococcal strain from which they were isolated.

scholarly journals Single Amino Acid Polymorphisms of Pertussis Toxin Subunit S2 (PtxB) Affect Protein Function

PLoS ONE ◽  
2015 ◽  
Vol 10 (9) ◽  
pp. e0137379 ◽  
Author(s):  
Scott H. Millen ◽  
Mineo Watanabe ◽  
Eiji Komatsu ◽  
Fuminori Yamaguchi ◽  
Yuki Nagasawa ◽  
...  
Keyword(s):  
Amino Acid ◽  
Pertussis Toxin ◽  
Protein Function ◽  
Single Amino Acid ◽  
Affect Protein Function ◽  
Single Amino Acid Polymorphisms

Characterization of group A streptococcal M-proteins purified by two methods

1976 ◽  
Vol 22 (8) ◽  
pp. 1072-1082
Author(s):  
David C. Straus ◽  
Charles F. Lange
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Molecular Size ◽  
M Protein ◽  
M Proteins ◽  
Group A ◽  
Terminal Amino ◽  
High Concentrations

Ten different group A streptococcal M-protein preparations purified by trichloroacetic acid precipitation and three M-protein preparations purified by cellulose chromatography were examined by SDS and polyacrylamide gel electrophoresis, and analyzed for amino acid composition and N-terminal amino acids. Fingerprinting (both tryptic and chymotryptic) was performed on the cellulose-purified preparations of M1, M12, and M29 proteins which showed these proteins to be structurally related. Trypsin produced maps with 37 to 42 peptides, whereas chymotrypsin digestion resulted in 8 to 12 peptides, depending on the M-type. Sequencing was performed on the M12 protein and tentative identification of nine N-terminal amino acids was made. Molecular weights of the cellulose and TCA-purified M-proteins were determined by SDS gel electrophoresis and chromatography on G-200 Sephadex, with comparable results, indicating molecular size of at least 23 000. The amino acid analyses of the 10 TCA-purified proteins followed the patterns established for M-proteins, with high concentrations of lysine, aspartic acid, glutamic acid, alanine, and leucine. All 10 proteins had L-alanine as their N-terminal amino acid. Evidence for a one way cross-reaction between type 1 and type 29 streptococci was also found.

scholarly journals FACTORS AFFECTING THE CHAIN LENGTH OF GROUP A STREPTOCOCCI

1960 ◽  
Vol 112 (4) ◽  
pp. 687-698 ◽  
Author(s):  
Richard D. Ekstedt ◽  
Gene H. Stollerman
Keyword(s):  
Surface Antigens ◽  
M Protein ◽  
Specific Inhibition ◽  
Group A Streptococci ◽  
Factors Affecting ◽  
Low Concentrations ◽  
Group A ◽  
Virulent Group ◽  
Long Chain ◽  
Long Chains

Minute amounts of M protein were detected in culture supernates of virulent Group A streptococci by type-specific inhibition of the long chain and the bactericidal tests for anti-M antibody. The amount of M protein that was detected by the inhibition of these biological systems was less than could be demonstrated by precipitation tests. All strains of streptococci rich in M protein which were studied formed long chains when grown in sufficient concentrations of anti-M antibody. Very low concentrations of anti-M antibody escaped detection by the long chain test when strains of excessive M protein content were employed. Under such conditions the bactericidal test detected anti-M antibody more sensitively than the long chain test owing to the smaller inoculum employed in the former method. The scission of streptococcal chains may be inhibited by union of antibodies with surface antigens other than M protein. Long chains were formed when M-negative, R-positive strains were grown in sera containing anti-R antibody.

CHANGES IN VIRULENCE, M PROTEIN AND IgG Fc RECEPTOR ACTIVITY IN A TYPE 12 GROUP A STREPTOCOCCAL STRAIN DURING MOUSE PASSAGES

2009 ◽  
Vol 88B (1-6) ◽  
pp. 199-206
Author(s):  
Larissa A. Burova ◽  
Poul Christensen ◽  
R. Grubb ◽  
Anders Jonsson ◽  
Gunilla Samuelsson ◽  
...  
Keyword(s):  
Fc Receptor ◽  
Receptor Activity ◽  
M Protein ◽  
Group A ◽  
Streptococcal Strain

scholarly journals Group A Streptococcal Vir Types Are M-Protein Gene (emm) Sequence Type Specific

1998 ◽  
Vol 36 (4) ◽  
pp. 902-907 ◽  
Author(s):  
Don L. Gardiner ◽  
Alison M. Goodfellow ◽  
Diana R. Martin ◽  
Kadaba S. Sriprakash
Keyword(s):  
Virulence Genes ◽  
Protein Gene ◽  
Fragment Length Polymorphism ◽  
Point Mutations ◽  
Rflp Analysis ◽  
Sequence Type ◽  
M Protein ◽  
Group A ◽  
Sequence Types ◽  
M Protein Genes

The M-protein genes (emm genes) of 103 separate impetiginous Streptococcus pyogenes isolates were sequenced and the sequence types were compared to the types obtained by Vir typing. Vir typing is based on restriction fragment length polymorphism (RFLP) analysis of a 4- to 7-kb pathogenicity island encodingemm and other virulence genes. By using bothHaeIII and HinfI to generate RFLP profiles, complete concordance between Vir type and emm sequence type was found. Comparison of the emm sequences with those in GenBank revealed new sequence types sharing less than 90% identity with known types. Diversity in the emm sequence was generated by corrected frameshift mutations, point mutations, and small in-frame mutations.

scholarly journals Purification and properties of M protein extracted from group A streptococci with pepsin: covalent structure of the amino terminal region of type 24 M antigen

1977 ◽  
Vol 145 (6) ◽  
pp. 1469-1483 ◽  
Author(s):  
EH Beachey ◽  
GH Stollerman ◽  
EY Chiang ◽  
TM Chiang ◽  
JM Seyer ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Terminal Region ◽  
M Protein ◽  
Skin Tests ◽  
Edman Degradation ◽  
Group A Streptococci ◽  
Passive Hemagglutination ◽  
Amino Terminal ◽  
Group A

M protein was extracted from type 24, group A streptococci with pepsin at pH 5.8 and was further purified by ammonium sulfate precipitation, ribonuclease digestion, ion-exchange chromatography, and isoelectric focusing. The purified pepsin extract of M (pep M) protein was shown to be free of nontype-specific immunoreactivity in (a) complement fixation tests with heterologous M antiserum, (b) skin tests in normal adult guinea pigs, and (c) passive hemagglutination tests for the presence of lipoteichoic acid sensitizing or antigenic activity. The pep M24 was highly immunogenic; two of three rabbits developed opsonic antibody titers of 1:256 and the third a titer of 1:32 6 wk after a single injection of 100-pg doses of pep M24 emulsified in complete Freund's adjuvant. The antisera lacked nontype-specific antibodies and produced single precipitin lines in agar gel diffusion tests against crude HC1 extracts of the homologous M protein. Thus, the type-specific antigenic determinant(s) of type 24 M protein appears to be separable from immunotoxic, cross-reactive antigens without loss of immunogenicity in rabbits. The mobility of pep M24 upon electrophoresis in 10 percent sodium dodecyl sulfate pelyacrylamide gel was consistent with an average mol wt of 33,500 daltons. Amino acid analysis demonstrated a predominance of alanine, followed by glutamic acid, lysine, leucine, and aspartic acid. Pep M24 contained an estimated six to seven methionine residues and approximately ten phenylalanine residues per molecule. No other aromatic amino acids were detected. Automatic Edman degradation of pep M24 yielded the sequence of the first 29 amino acids (the amino terminal amino acid being valine) of the amino terminal region of the molecule. The detection of only one new amino acid at each step of Edman degradation confirmed the homogeneity of the purified pep M24.

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