Alexei G. Prilipov

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Combination of an origin repair mutagenesis system with a new mutS host strain increased the efficiency of mutagenesis from 46% to 75% mutant clones. Overexpression with the T7 expression system afforded large quantities of proteins from mutant strains. A series of E. coli BE host strains devoid of major outer membrane proteins was constructed, facilitating(More)
The porins PhoE and OmpF form anion and cation-selective pores, respectively, in the outer membrane of Escherichia coli. Each monomer of these trimeric proteins consists of a 16-stranded beta-barrel, which contains a constriction at half the height of the channel. The functional significance of a transverse electrical field that is formed by charged amino(More)
The genomic DNA of the BE strain of Escherichia coli has been scrutinized to detect porin genes that have not been identified so far. Southern blot analysis yielded two DNA segments which proved highly homologous to, yet distinct from, the ompC, ompF, and phoE porin genes. The two genes were cloned and sequenced. One of them, designated ompN, encodes a(More)
The sole histidine residue in OmpF porin was replaced by threonine using site-directed mutagenesis. This exchange affected neither channel properties nor channel structure, as determined by X-ray analysis to 3.2 A. Conductance and critical voltage (Vc) were observed in the pH range 4.3-9.4, with results indistinguishable from those observed in the wild-type(More)
Sequence analysis of approximately 25kb of an Azospirillum brasilense Sp245 85-MDa ( approximately 142kb) plasmid, p85, identified two novel IS elements mediating p85 fusions with a suicide plasmid vector, pJFF350. These IS elements, 1465-bp ISAzba1 and 1112-bp ISAzba3, belong to the IS256 family and to the IS5 family/IS903 group, respectively. Truncated(More)
Abstract Influenza virus nucleoprotein (NP) binds to the viral genome RNA and forms the internal ribonucleoprotein complex of the virus particle. Avian and human influenza virus NP have characteristic differences at several amino acid positions. It is not known whether any of these differences can be recognized by antibodies. In the present study five(More)
In the homotrimeric OmpF porin from Escherichia coli, each channel is constricted by a loop protruding into the beta-barrel of the monomer about halfway through the membrane. The water-filled channels exist in open or closed states, depending on the transmembrane potential. For the transition between these conformations, two fundamentally different(More)
The locations of amino acid positions relevant to antigenic variation in the nucleoprotein (NP) of influenza virus are not conclusively known. We analysed the antigenic structure of influenza A virus NP by introducing site-specific mutations at amino acid positions presumed to be relevant for the differentiation of strain differences by anti-NP monoclonal(More)
Numerous attempts to induce immunity against HCV core (HCV-C) by DNA immunization met serious difficulties in optimizing T-helper cell and antibody responses. Immunomodulatory properties of HCV-C could be blamed that seem to be dependent on the genotype of HCV source. Here, we characterized HCV-C gene from HCV 1b isolate 274933RU. Eukaryotic expression of(More)
  • Patrick Van Gelder, Fabrice Dumas, +7 authors Tilman Schirmer
  • Journal of bacteriology
  • 2002
The lining of the maltodextrin-specific maltoporin (LamB) channel exhibits a string of aromatic residues, the greasy slide, part of which has been shown previously by crystallography to be involved in substrate binding. To probe the functional role of the greasy slide, alanine scanning mutagenesis has been performed on the six greasy slide residues and Y118(More)