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001-es BibID:BIBFORM040736
Első szerző:Kádas János (molekuláris biológus, biokémikus, kertészmérnök)
Cím:Narrow Substrate Specificity and Sensitivity toward Ligand-binding Site Mutations of Human T-cell Leukemia Virus Type 1 Protease / Kádas J., Weber I. T., Bagossi P., Miklóssy G., Boross P., Oroszlan S., Tözsér J.
Dátum:2004
ISSN:0021-9258
Megjegyzések:Human T-cell leukemia virus type 1 (HTLV-1) is associated with a number of human diseases; therefore, its protease is a potential target for chemotherapy. To compare the specificity of HTLV-1 protease with that of human immunodeficiency virus type 1 (HIV-1) protease, oligopeptides representing naturally occurring cleavage sites in various retroviruses were tested. The number of hydrolyzed peptides as well as the specificity constants suggested a substantially broader specificity of the HIV protease. Amino acid residues of HTLV-1 protease substrate-binding sites were replaced by equivalent ones of HIV-1 protease. Most of the single and multiple mutants had altered specificity and a dramatically reduced folding and catalytic capability, suggesting that mutations are not well tolerated in HTLV-1 protease. The catalytically most efficient mutant was that with the flap residues of HIV-1 protease. The inhibition profile of the mutants was also determined for five inhibitors used in clinical practice and inhibitor analogs of HTLV-1 cleavage sites. Except for indinavir, the HIV-1 protease inhibitors did not inhibit wild type and most of the mutant HTLV-1 proteases. The wild type HTLV-1 protease was inhibited by the reduced peptide bond-containing substrate analogs, whereas the mutants showed various degrees of weakened binding capability. Most interesting, the enzyme with HIV-1-like residues in the flap region was the most sensitive to the HIV-1 protease inhibitors and least sensitive to the HTLV-1 protease inhibitors, indicating that the flap plays an important role in defining the specificity differences of retroviral proteases.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Journal Of Biological Chemistry. - 279 : 26 (2004), p. 27148-27157. -
További szerzők:Weber, Irene T. Bagossi Péter (1966-2011) (biokémikus, vegyész) Miklóssy Gabriella (1979-) (biológus, vegyész) Boross Péter (1972-) (biokémikus, vegyész) Oroszlan, Stephen Tőzsér József (1959-) (molekuláris biológus, biokémikus, vegyész)
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Intézményi repozitóriumban (DEA) tárolt változat
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2.

001-es BibID:BIBFORM040699
Első szerző:Tőzsér József (molekuláris biológus, biokémikus, vegyész)
Cím:Comparative studies on the substrate specificity of avian myeloblastosis virus proteinase and lentiviral proteinases / Tözsér J., Bagossi P., Weber I. T., Copeland T. D., Oroszlan S.
Dátum:1996
Megjegyzések:The retroviral proteinase (PR) seems to play crucial roles in the viral life cycle, therefore it is an attractive target for chemotherapy. Previously we studied the specificity of human immunodeficiency virus (HIV) type 1 and type 2 as well as equine infectious anemia virus PRs using oligopeptide substrates. Here a similar approach is used to characterize the specificity of avian myeloblastosis virus (AMV) PR and to compare it with those of the previously characterized lentiviral PRs. All peptides representing naturally occurring Gag and Gag-Pol cleavage sites were substrates of the AMV PR. Only half of these peptides were substrates of HIV-1 PR. The Km values for AMV PR were in a micromolar range previously found for the lentiviral PRs; however, the kcat values were in a 10 30-fold lower range. A series of peptides containing single amino acid substitutions in a sequence representing a naturally occurring HIV cleavage site was used to characterize the seven substrate binding subsites of the AMV PR. The largest differences were found at the P4 and P2 positions of the substrate. Detailed analysis of the results by molecular modeling and comparison with previously reported data revealed the common characteristics of the specificity of the retroviral PRs as well as its strong dependence on the sequence context of the substrate.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:The Journal of biological chemistry. - 271 : 12 (1996), p. 6781-6788. -
További szerzők:Bagossi Péter (1966-2011) (biokémikus, vegyész) Weber, Irene T. Copeland, Terry D. Oroszlan, Stephen
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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3.

001-es BibID:BIBFORM040701
Első szerző:Tőzsér József (molekuláris biológus, biokémikus, vegyész)
Cím:Studies on the Symmetry and Sequence Context Dependence of the HIV-1 Proteinase Specificity / Tözsér J., Bagossi P., Weber I. T., Louis J. M., Copeland T. D., Oroszlan S.
Dátum:1997
ISSN:0021-9258
Megjegyzések:Two major types of cleavage sites with different sequence preferences have been proposed for the human immunodeficiency virus type 1 (HIV-1) proteinase. To understand the nature of these sequence preferences better, single and multiple amino acid substitutions were introduced into a type 1 cleavage site peptide, thus changing it to a naturally occurring type 2 cleavage site sequence. Our results indicated that the previous classification of the retroviral cleavage sites may not be generally valid and that the preference for a residue at a particular position in the substrate depends strongly on the neighboring residues, including both those at the same side and at the opposite side of the peptide backbone of the substrate. Based on these results, pseudosymmetric (palindromic) substrates were designed. The retroviral proteinases are symmetrical dimers of two identical subunits; however, the residues of naturally occurring cleavage sites do not show symmetrical arrangements, and no obvious symmetrical substrate preference has been observed for the specificity of HIV proteinase. To examine the role of the asymmetry created by the peptide bonds on the specificity of the respective primed and nonprimed halves of the binding site, amino acid substitutions were introduced into a palindromic sequence. In general, the results suggested that the asymmetry does not result in substantial differences in specificity of the S3 and S3' subsites, whereas its effect is more pronounced for the S2 and S2' subsites. Although it was possible to design several good palindromic substrates, asymmetrical arrangements may be preferred by the HIV proteinase.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Journal Of Biological Chemistry. - 272 : 27 (1997), p. 16807-16814. -
További szerzők:Bagossi Péter (1966-2011) (biokémikus, vegyész) Weber, Irene T. Louis, John M. Copeland, Terry D. Oroszlan, Stephen
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DOI
Intézményi repozitóriumban (DEA) tárolt változat
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