scholarly journals Characterization of a Predominant Immunogenic Outer Membrane Protein of Riemerella anatipestifer

2000 ◽  
Vol 7 (2) ◽  
pp. 168-174 ◽  
Author(s):  
Sumathi Subramaniam ◽  
Bin Huang ◽  
Hilda Loh ◽  
Jimmy Kwang ◽  
Hai-Meng Tan ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Calcium Binding ◽  
Outer Membrane Proteins ◽  
Terminal Region ◽  
Gene Encoding ◽  
Riemerella Anatipestifer ◽  
Binding Domains

ABSTRACT The ompA gene, encoding the 42-kDa major antigenic outer membrane protein OmpA of Riemerella anatipestifer, the etiololgical agent of septicemia anserum exsudativa, was cloned and expressed in Escherichia coli. Recombinant OmpA displayed a molecular mass similar to that predicted from the nucleotide sequence of the ompA gene but lower than that observed in total cell lysates of R. anatipestifer. The ompA gene showed a conserved C-terminal region comprising the OmpA-like domain and a variable N-terminal region. This structure is similar to those of the analogous outer membrane proteins of several gram-negative bacteria. However, OmpA of R. anatipestifercontains six EF-hand calcium-binding domains and two PEST regions, which distinguish it from other outer membrane proteins. The occurrence of these motifs in OmpA suggests a possible role in virulence for this protein. The ompA gene is present in the R. anatipestifer type strain and in all serotype reference strains. However, it exhibits some minor genetic heterogeneity among different serotypes, which seems not to affect the strong antigenic characteristics of the protein. OmpA is a conserved and strong antigenic determinant of R. anatipestifer and hence is suggested to be a valuable protein for the serodetection of R. anatipestifer infections, independent of their serotype.

Outer Membrane Protein Composition in Disease Isolates of Haemophilus influenzae : Pathogenic and Epidemiological Implications

1980 ◽  
Vol 30 (3) ◽  
pp. 709-717
Author(s):  
Marilyn R. Loeb ◽  
David H. Smith
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Haemophilus Influenzae ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Protein Composition ◽  
The Other ◽  
Major Protein ◽  
Single Strain

The outer membrane protein composition of 50 disease isolates of Haemophilus influenzae has been determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. All strains, including 28 strains of serotype b , one strain each of serotypes a, c, d, e , and f , and 17 untypable strains, had an outer membrane protein composition typical of gram-negative bacteria, i.e., these membranes contained two to three dozen proteins with four to six proteins accounting for most of their protein content. Variation in the mobility of these major outer membrane proteins from strain to strain was common but not universal; the observed patterns provided useful data and new insight into the epidemiology of type b disease. The basic findings can be summarized as follows: (i) All 50 strains possessed three proteins (one minor and two major) each having identical mobilities. The other proteins, both major and minor, varied in mobility. (ii) All type b strains possessed a fourth (major) protein of identical mobility. (iii) The 28 type b strains, on the basis of the mobility of the six major outer membrane proteins, could be divided into eight subtypes. Of all the other strains examined, both typable and untypable, only the serotype a strain belonged to one of these subtypes. (iv) The untypable strains showed considerable variation in the mobilities of their major outer membrane proteins. Of these 17 strains, 13 had an additional major outer membrane protein not present in encapsulated strains. (v) The outer membrane protein composition of a single strain remained unchanged after many passages on solid media, but varied with the growth phase. (vi) The outer membrane protein composition of isolates obtained from nine patients during an epidemic of type b meningitis varied, indicating that a single strain was not responsible for the epidemic. At least five different strains were responsible for these nine cases. (vii) Identical outer membrane protein compositions were observed in the following: in a type b strain and a mutant of this strain deficient in capsule production, indicating that the level of capsule synthesis is not obviously related to outer membrane protein composition; in type b strains isolated from different anatomic sites of patients acutely ill with meningitis, indicating that the strain associated with bacteremia is the same as that isolated from the cerebrospinal fluid; in type b strains isolated from siblings who contracted meningitis at about the same time, indicating infection with the same strain; and in type b strains isolated from the initial and repeat infection of a single patient, suggesting that reinfection was due to the same strain.

scholarly journals Characterization of Outer Membrane Proteins in Chlamydia trachomatis LGV Serovar L2

2001 ◽  
Vol 183 (8) ◽  
pp. 2686-2690 ◽  
Author(s):  
Regina J. Tanzer ◽  
Thomas P. Hatch
Keyword(s):  
Chlamydia Trachomatis ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Major Outer Membrane Protein ◽  
Developmental Cycle ◽  
Reading Frame

ABSTRACT We used a photoactivatable, lipophilic reagent, 3′-(trifluoromethyl)-3-(m-[125I]iodophenyl)diazirine, to label proteins in the outer membrane of elementary bodies ofChlamydia trachomatis LGV serovar L2 and mass spectrometry to identify the labeled proteins. The identified proteins were polymorphic outer membrane proteins E, G, and H, which were made late in the developmental cycle, the major outer membrane protein, and a mixture of 46-kDa proteins consisting of the open reading frame 623 protein and possibly a modified form of the major outer membrane protein.

scholarly journals Assembly of TolC, a Structurally Unique and Multifunctional Outer Membrane Protein of Escherichia coli K-12

2003 ◽  
Vol 185 (22) ◽  
pp. 6540-6547 ◽  
Author(s):  
John Werner ◽  
Anne Marie Augustus ◽  
Rajeev Misra
Keyword(s):  
Escherichia Coli ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
The Other ◽  
Proteinase K ◽  
Folded Structure ◽  
K 12

ABSTRACT TolC is a multifunctional outer membrane protein of Escherichia coli that folds into a novel α-β-barrel conformation absent in the other model outer membrane proteins used in assembly studies. The data presented in this work show that the unique folded structure of TolC reflects a unique assembly pathway. During its assembly, the newly translocated nascent TolC monomers are released in the periplasm. Maturation of these nascent monomers, and possibly their oligomerization, in the periplasm precedes their insertion in the outer membrane. The completion of the assembly process is signaled by the development of a characteristic proteinase K-resistant fragment generated by cleavage at a single, periplasmically exposed, protease-sensitive site of the membrane-anchored trimer. None of the assembly steps of TolC is affected by known folding factors, such as SurA, Skp, and lipopolysaccharide, which have profound effects on the assembly of other model trimeric outer membrane proteins. Two assembly-defective TolC mutants were isolated and characterized. One of the mutants (TolCI106N) was defective in the folding of nascent monomers, while the other (TolCS350F) was impaired in steps involving trimerization and membrane insertion of folded monomers.

scholarly journals Type-specific antigens of group A Neisseria meningitidis: lipopolysaccharide and heat-modifiable outer membrane proteins

1980 ◽  
Vol 28 (2) ◽  
pp. 451-458 ◽  
Author(s):  
W D Zollinger ◽  
R E Mandrell
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Neisseria Meningitidis ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Solid Phase ◽  
Outer Membrane Proteins ◽  
Surface Antigens ◽  
Protein Antigens ◽  
Group A

The solid-phase radioimmunoassay inhibition method was used to analyze the noncapsular surface antigens of group A Neisseria meningitidis for type specificity. By use of antisera prepared against group A strains, three serologically distinct lipopolysaccharide antigens and five outer membrane protein antigens were identified among group A strains from a variety of geographical origins. Two of the lipopolysaccharide antigens were unique to group A strains while the third was similar to those on strains of other meningococcal serogroups. Fractionation of outer membrane proteins in the presence of 2% sodium deoxycholate followed by quantitative inhibition of the typing reactions with the subfractions revealed that the protein responsible for type specificity was not the principal outer membrane protein, but, most likely, the 31,000-dalton, heat-modifiable outer membrane protein. Thus, although group A strains may share a common principal outer membrane protein, typing is feasible using other surface antigens. In a survey of 82 group A strains, 93% were typable with respect to outer membrane proteins.

scholarly journals Cloning and Functional Analysis of the Gene Encoding the 33- to 36-Kilodalton Outer Membrane Protein Associated with Carbapenem Resistance in Acinetobacter baumannii

2005 ◽  
Vol 49 (12) ◽  
pp. 5172-5175 ◽  
Author(s):  
Maria del Mar Tomás ◽  
Alejandro Beceiro ◽  
Astrid Pérez ◽  
David Velasco ◽  
Rita Moure ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Membrane Protein ◽  
Acinetobacter Baumannii ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Carbapenem Resistance ◽  
Peptide Sequence ◽  
Gene Encoding ◽  
Multiresistant Strain

ABSTRACT We investigated a multiresistant strain of Acinetobacter baumannii isolated in our hospital. Analysis of the N-terminal peptide sequence of the outer membrane proteins (OMPs) purified from the strain allowed us to clone and sequence the nucleotides of the gene encoding the 33- to 36-kDa OMP associated with carbapenem resistance in A. baumannii

scholarly journals Protective Efficacy of DNA Vaccines Encoding Outer Membrane Protein A and OmpK36 ofKlebsiella pneumoniaein Mice

2010 ◽  
Vol 18 (1) ◽  
pp. 82-88 ◽  
Author(s):  
Prathiba Kurupati ◽  
N. P. Ramachandran ◽  
Chit Laa Poh
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Dna Vaccines ◽  
Outer Membrane Proteins ◽  
Protein A ◽  
Interleukin 12 ◽  
Th2 Response ◽  
Outer Membrane Protein A

ABSTRACTThe immunogenicity of DNA vaccines expressing outer membrane proteins as antigens was evaluated in this study. DNA vaccines consisting of vector pVAX1 expressing either outer membrane protein A or OmpK36 were injected into mice by either the intradermal or the intramuscular route. Antibodies elicited were shown to be specifically reactive to OmpA and OmpK36 by immunoblotting. The immunoglobulin G (IgG) antibodies elicited by both vaccines included IgG1, IgG2a, IgG2b, and IgG3. Immunized mice exhibited a predominance of IgG1 over IgG2a, therefore indicating a stronger humoral response. Mice receiving either of the DNA vaccines produced high levels of interleukin-12 (IL-12) and IL-10 and low levels of gamma interferon, suggesting the induction of a mixed Th1 and Th2 response. Sera from DNA vaccine-immunized mice had significantly higher opsonic activity in opsonophagocytic assays than did sera from the control mice. The level of protection afforded by pOmpK36 DNA injected intradermally into mice was the highest. These results suggest that both OmpA and OmpK36 are excellent candidates for use in future studies of vaccination against infections caused byKlebsiella pneumoniae. This is the first study which established the efficacy of protection afforded by DNA vaccines based on outer membrane proteins againstK. pneumoniaeinfections.

scholarly journals Redesigning OmpA Loops Using Canonical Outer Membrane Protein Loop Structures

2020 ◽  
Author(s):  
Meghan W. Franklin ◽  
Joanna Krise ◽  
Jacqueline J. Stevens ◽  
Joanna S.G. Slusky
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Loop Conformations ◽  
Beta Barrels ◽  
Protein Loops

ABSTRACTProtein loops can be difficult to design and predict. There have been multiple different algorithms developed to predict the structure of loops. Outer membrane proteins are all beta barrels and these barrels have a variety of well-documented loop conformations. Here we test three different algorithms to predict the structure of outer membrane protein loops. We find the PETALS algorithm is superior for this purpose. We then experimentally test the effect of replacing the long loops of outer membrane protein OmpA with twelve shorter designed loops. Though we succeeded in creating the smallest known outer membrane barrel, we find that the designed loops do not have a strong effect on OmpA folding.

Acid stress upregulated outer membrane proteins in clinical isolates ofNeisseria gonorrhoeae, but not most commensalNeisseria

2001 ◽  
Vol 47 (9) ◽  
pp. 871-876 ◽  
Author(s):  
R K Pettit ◽  
T M Whelan ◽  
K S Woo
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Neisseria Gonorrhoeae ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Acid Stress ◽  
Immune Serum ◽  
Gonococcal Infection ◽  
Membrane Components

Human immune serum recognition of outer membrane components from commensal and pathogenic Neisseria cultured under neutral and acidic conditions was investigated. Acid stress caused no detectable alterations in lipooligosaccharide migration and (or) staining, in outer membrane protein profiles, or in immune serum recognition of outer membrane components from Neisseria mucosa or Neisseria sicca. There was also no difference in the lipoologosaccharide electrophoretic pattern of acid- and neutral-grown Neisseria lactamica, but there were differences in outer membrane protein expression. The outer membrane protein alterations induced by acid stress in N. lactamica were not the same as those seen in isolates from patients with uncomplicated gonococcal infection, pelvic inflammatory disease, and disseminated gonococcal infection. Many differences were detected in the immune serum recognition of outer membrane components from acid- and neutral-cultured N. lactamica and from the clinical isolates of Neisseria gonorrhoeae, and these should be considered in vaccine design.Key words: Neisseria gonorrhoeae, commensal Neisseria, acid stress, outer membrane proteins.

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