scholarly journals Novel Genetic and Phenotypic Heterogeneity in Bordetella bronchiseptica Pertactin

2001 ◽  
Vol 69 (3) ◽  
pp. 1917-1921 ◽  
Author(s):  
Karen B. Register
Keyword(s):  
Amino Acid ◽  
Sequence Analysis ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Dna Sequence ◽  
Outer Membrane Protein ◽  
Phenotypic Heterogeneity ◽  
Bordetella Bronchiseptica ◽  
Amino Acid Repeat ◽  
Sequence Heterogeneity

ABSTRACT The Bordetella bronchiseptica outer membrane protein pertactin is believed to function as an adhesin and is an important protective immunogen. Previous sequence analysis of the pertactin gene identified two regions predicted to encode amino acid repeat motifs. Recent studies have documented DNA sequence heterogeneity in both regions. The present study describes additional variants in these regions, which form the basis for six novel pertactin types. Immunoblotting demonstrated phenotypic heterogeneity in pertactin consistent with the predicted combined sizes of the repeat regions. A revised system for classifying B. bronchiseptica pertactin variants is proposed.

scholarly journals Genetic Diversity of the 28-Kilodalton Outer Membrane Protein Gene in Human Isolates of Ehrlichia chaffeensis

1999 ◽  
Vol 37 (4) ◽  
pp. 1137-1143 ◽  
Author(s):  
Xue-Jie Yu ◽  
Jere W. McBride ◽  
David H. Walker
Keyword(s):  
Amino Acid ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Dna Sequence ◽  
Outer Membrane Protein ◽  
Signal Sequence ◽  
Outer Membrane Proteins ◽  
Protein A ◽  
Amino Acid Sequences ◽  
Ehrlichia Chaffeensis

The Ehrlichia chaffeensis 28-kDa outer membrane protein (p28) gene was sequenced completely by genomic walking with adapter PCR. The DNA sequence of the p28 gene was nearly identical to the previously reported sequence (N. Ohashi, N. Zhi, Y. Zhang, and Y. Rikihisa, Infect. Immun. 66:132–139, 1998), but analysis of a further 75 bp on the 5′ end of the gene revealed DNA that encoded a 25-amino-acid signal sequence. The leader sequence was removed from the N terminus of a 30-kDa precursor to generate the mature p28 protein. A monoclonal antibody (MAb), 1A9, recognizing four outer membrane proteins of E. chaffeensis (Arkansas strain) including the 25-, 26-, 27-, and 29-kDa proteins (X.-J. Yu, P. Brouqui, J. S. Dumler, and D. Raoult, J. Clin. Microbiol. 31:3284–3288, 1993) reacted with the recombinant p28 protein. This result indicated that the four proteins recognized by MAb 1A9 were encoded by the multiple genes of the 28-kDa protein family. DNA sequence alignment analysis revealed divergence of p28 among all five human isolates of E. chaffeensis. The E. chaffeensis strains could be divided into three genetic groups on the basis of the p28 gene. The first group consisted of the Sapulpa and St. Vincent strains. They had predicted amino acid sequences identical to each other. The second group contained strain 91HE17 and strain Jax, which only showed 0.4% divergence from each other. The third group contained the Arkansas strain only. The amino acid sequences of p28 differed by 11% between the first two groups, by 13.3% between the first and third groups, and by 13.1% between the second and third groups. The presence of antigenic variants of p28 among the strains of E. chaffeensis and the presence of multiple copies of heterogeneous genes suggest a possible mechanism by which E. chaffeensismight evade the host immune defenses. Whether or not immunization with the p28 of one strain of E. chaffeensis would confer cross-protection against other strains needs to be investigated.

scholarly journals Porin activity and sequence analysis of a 31-kilodalton Treponema pallidum subsp. pallidum rare outer membrane protein (Tromp1).

1995 ◽  
Vol 177 (12) ◽  
pp. 3556-3562 ◽  
Author(s):  
D R Blanco ◽  
C I Champion ◽  
M M Exner ◽  
H Erdjument-Bromage ◽  
R E Hancock ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Treponema Pallidum

scholarly journals Sequence Polymorphism, Predicted Secondary Structures, and Surface-Exposed Conformational Epitopes of Campylobacter Major Outer Membrane Protein

2000 ◽  
Vol 68 (10) ◽  
pp. 5679-5689 ◽  
Author(s):  
Qijing Zhang ◽  
Jerrel C. Meitzler ◽  
Shouxiong Huang ◽  
Teresa Morishita
Keyword(s):  
Amino Acid ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Major Outer Membrane Protein ◽  
Amino Acid Sequences ◽  
Variable Regions ◽  
Conserved Sequences ◽  
Conformational Epitopes

ABSTRACT The major outer membrane protein (MOMP), a putative porin and a multifunction surface protein of Campylobacter jejuni, may play an important role in the adaptation of the organism to various host environments. To begin to dissect the biological functions and antigenic features of this protein, the gene (designatedcmp) encoding MOMP was identified and characterized from 22 strains of C. jejuni and one strain of C. coli. It was shown that the single-copy cmp locus encoded a protein with characteristics of bacterial outer membrane proteins. Prediction from deduced amino acid sequences suggested that each MOMP subunit consisted of 18 β-strands connected by short periplasmic turns and long irregular external loops. Alignment of the amino acid sequences of MOMP from different strains indicated that there were seven localized variable regions dispersed among highly conserved sequences. The variable regions were located in the putative external loop structures, while the predicted β-strands were formed by conserved sequences. The sequence homology of cmp appeared to reflect the phylogenetic proximity of C. jejuni strains, since strains with identical cmp sequences had indistinguishable or closely related macrorestriction fragment patterns. Using recombinant MOMP and antibodies recognizing linear or conformational epitopes of the protein, it was demonstrated that the surface-exposed epitopes of MOMP were predominantly conformational in nature. These findings are instrumental in the design of MOMP-based diagnostic tools and vaccines.

scholarly journals Differentiation ofCoxiella burnetiiby Sequence Analysis of the Gene(com1)Encoding a 27-kDa Outer Membrane Protein

1997 ◽  
Vol 41 (11) ◽  
pp. 871-877 ◽  
Author(s):  
Guo Quan Zhang ◽  
Ho To ◽  
Tsuyoshi Yamaguchi ◽  
Hideto Fukushi ◽  
Katsuya Hirai
Keyword(s):  
Sequence Analysis ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein

scholarly journals Point mutations in the major outer membrane protein drive hypervirulence of a rapidly expanding clone of Campylobacter jejuni

2016 ◽  
Vol 113 (38) ◽  
pp. 10690-10695 ◽  
Author(s):  
Zuowei Wu ◽  
Balamurugan Periaswamy ◽  
Orhan Sahin ◽  
Michael Yaeger ◽  
Paul Plummer ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Campylobacter Jejuni ◽  
Outer Membrane Protein ◽  
Animal Health ◽  
Major Outer Membrane Protein ◽  
Whole Genome Sequence ◽  
Bacterial Strains ◽  
Zoonotic Pathogen

Infections due to clonal expansion of highly virulent bacterial strains are clear and present threats to human and animal health. Association of genetic changes with disease is now a routine, but identification of causative mutations that enable disease remains difficult. Campylobacter jejuni is an important zoonotic pathogen transmitted to humans mainly via the foodborne route. C. jejuni typically colonizes the gut, but a hypervirulent and rapidly expanding clone of C. jejuni recently emerged, which is able to translocate across the intestinal tract, causing systemic infection and abortion in pregnant animals. The genetic basis responsible for this hypervirulence is unknown. Here, we developed a strategy, termed “directed genome evolution,” by using hybridization between abortifacient and nonabortifacient strains followed by selection in an animal disease model and whole-genome sequence analysis. This strategy successfully identified SNPs in porA, encoding the major outer membrane protein, are responsible for the hypervirulence. Defined mutagenesis verified that these mutations were both necessary and sufficient for causing abortion. Furthermore, sequence analysis identified porA as the gene with the top genome-wide signal of adaptive evolution using Fu’s Fs, a population genetic metric for recent population size changes, which is consistent with the recent expansion of clone “sheep abortion.” These results identify a key virulence factor in Campylobacter and a potential target for the control of this zoonotic pathogen. Furthermore, this study provides general, unbiased experimental and computational approaches that are broadly applicable for efficient elucidation of disease-causing mutations in bacterial pathogens.

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