CCL

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1.

001-es BibID:BIBFORM040648
Első szerző:Boross Péter (biokémikus, vegyész)
Cím:Effect of substrate residues on the P2' preference of retroviral proteinases / Boross Peter, Bagossi Peter, Copeland Terry D., Oroszlan Stephen, Louis John M., Tozser Jozsef
Dátum:1999
ISSN:0014-2956
Megjegyzések:The substrate sequence requirements for preference toward P2' Glu residue by human immunodeficiency virus type 1 (HIV-1) proteinase were studied in both the matrix protein/ capsid protein (MA/CA) and CA/p2 cleavage site sequence contexts. These sequences represent typical type 1 (-aromatic*Pro-) and type 2 (-hydrophobic* hydrophobic-) cleavage site sequences, respectively. While in the type 1 sequence context, the preference for P2' Glu over Ile or Gln was found to be strongly dependent on the ionic strength and the residues being outside the P2-P2' region of the substrate, it remained preferable in the type 2 substrates when typical type 1 substrate sequence residues were substituted into the outside regions. The pH profile of the specificity constants suggested a lower pH optimum for substrates having P2' Glu in contrast to those having uncharged residues, in both sequence contexts. The very low frequency of P2' Glu in naturally occurring retroviral cleavage sites of various retroviruses including equine infectious anemia virus (EIAV) and murine leukemia virus (MuLV) suggests that such a residue may not have a general regulatory role in the retroviral life cycle. In fact, unlike HIV-1 and HIV-2, EIAV and MuLV proteinases do not favor P2' Glu in either the MA/CA or CA/p2 sequence contexts.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:European Journal Of Biochemistry. - 264 : 3 (1999), p. 921-929. -
További szerzők:Bagossi Péter (1966-2011) (biokémikus, vegyész) Copeland, Terry D. Oroszlan, Stephen Louis, John M. Tőzsér József (1959-) (molekuláris biológus, biokémikus, vegyész)
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2.

001-es BibID:BIBFORM040655
Első szerző:Fehér Anita
Cím:Effect of sequence polymorphism and drug resistance on two HIV-1 Gag processing sites / Fehér Anita, Weber Irene T., Bagossi Péter, Boross Péter, Mahalingam Bhuvaneshwari, Louis John M., Copeland Terry D., Torshin Ivan Y., Harrison Robert W., Tözsér József
Dátum:2002
ISSN:0014-2956
Megjegyzések:The HIV-1 proteinase (PR) has proved to be a good target for antiretroviral therapy of AIDS, and various PR inhibitors are now in clinical use. However, there is a rapid selection of viral variants bearing mutations in the proteinase that are resistant to clinical inhibitors. Drug resistance also involves mutations of the nucleocapsid/p1 and p1/p6 cleavage sites of Gag, both in vitro and in vivo. Cleavages at these sites have been shown to be rate limiting steps for polyprotein processing and viral maturation. Furthermore, these sites show significant sequence polymorphism, which also may have an impact on virion infectivity. We have studied the hydrolysis of oligopeptides representing these cleavage sites with representative mutations found as natural variations or that arise as resistant mutations. Wild-type and five drug resistant PRs with mutations within or outside the substrate binding site were tested. While the natural variations showed either increased or decreased susceptibility of peptides toward the proteinases, the resistant mutations always had a beneficial effect on catalytic efficiency. Comparison of the specificity changes obtained for the various substrates suggested that the maximization of the van der Waals contacts between substrate and PR is the major determinant of specificity: the same effect is crucial for inhibitor potency. The natural nucleocapsid/p1 and p1/p6 sites do not appear to be optimized for rapid hydrolysis. Hence, mutation of these rate limiting cleavage sites can partly compensate for the reduced catalytic activity of drug resistant mutant HIV-1 proteinases.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:European Journal Of Biochemistry. - 269 : 16 (2002), p. 4114-4120. -
További szerzők:Weber, Irene T. Bagossi Péter (1966-2011) (biokémikus, vegyész) Boross Péter (1972-) (biokémikus, vegyész) Mahalingam, Bhuvaneshwari Louis, John M. Copeland, Terry D. Torshin, Ivan Y. Harrison, Robert W. Tőzsér József (1959-) (molekuláris biológus, biokémikus, vegyész)
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3.

001-es BibID:BIBFORM040689
Első szerző:Tőzsér József (molekuláris biológus, biokémikus, vegyész)
Cím:Activity of Tethered Human Immunodeficiency Virus 1 Protease Containing Mutations in the Flap Region of One Subunit / Tozser Jozsef, Yin Fay H., Cheng Yin-Shyun E., Bagossi Peter, Weber Irene T., Harrison Robert W., Oroszlan Stephen
Dátum:1997
ISSN:0014-2956
Megjegyzések:The tethered-dimer protease of human immunodeficiency virus 1 (HIV-1) [Cheng Y.-S. E., Yin, F.H., Foundling, S., Blomstrom, D. & Kettner, C. A. (1990) Proc. Natl Acad. Sci. USA 87, 9660-9664] and its mutants containing amino acid substitutions or deletions or both in only one flap region were expressed in Escherichia coli. These mutant enzymes showed various degrees of self-processing and significantly reduced catalytic activity toward oligopeptide substrates compared with the wild type. Kinetic parameters determined for one of the oligopeptide substrates showed a dramatic increase in K(m) and decrease in Kcat values. Unexpectedly, the substrate cleavage was more efficient in low salt concentration for a mutant containing a shortened hydrophilic flap. Assays with oligopeptides representing naturally occurring cleavage sites or oligopeptides containing single amino acid substitutions at the P2 and P2' substrate positions showed only moderate changes in the substrate specificity of the mutant proteases. Predicted structures for the mutants were constructed by molecular modeling and used to interpret the results of kinetic measurements. In general, the data suggest that the mutated part of the flaps does not have a major role in determining substrate specificity; rather, it provides the hydrophobic environment and hydrogen-bond interactions with the conserved water that are necessary for efficient substrate binding and catalysis.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:European Journal Of Biochemistry 244 : 1 (1997), p. 235-241. -
További szerzők:Yin, Fay H. Cheng, Yin-Shyun E. Bagossi Péter (1966-2011) (biokémikus, vegyész) Weber, Irene T. Harrison, Robert W. Oroszlan, Stephen
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4.

001-es BibID:BIBFORM040690
Első szerző:Tőzsér József (molekuláris biológus, biokémikus, vegyész)
Cím:Effect of serine and tyrosine phosphorylation on retroviral proteinase substrates / Tozser Jozsef, Bagossi Peter, Boross Peter, Louis John M., Majerova Eva, Oroszlan Stephen, Copeland Terry D.
Dátum:1999
ISSN:0014-2956
Megjegyzések:Vimentin, a cellular substrate of HIV type 1 (HIV-1) proteinase, contains a protein kinase C (PKC) phosphorylation site at one of its cleavage sites. Peptides representing this site were synthesized in P2 Ser-phosphorylated and nonphosphorylated forms. While the nonphosphorylated peptide was a fairly good substrate of the enzyme, phosphorylation prevented hydrolysis. Phosphorylation of human recombinant vimentin by PKC prevented its processing within the head domain, where the phosphorylation occurred. Oligopeptides representing naturally occurring cleavage sites at the C-terminus of the Rous sarcoma virus integrase were assayed as substrates of the avian proteinase. Unlike the nonphosphorylated peptides, a Ser-phosphorylated peptide was not hydrolyzed by the enzyme at the Ser-Pro bond, suggesting the role of previously established phosphorylation in processing at this site. Ser-phosphorylated and Tyr-phosphorylated forms of model substrates were also tested as substrates of the HIV-1 and the avian retroviral proteinases. In contrast to the moderate effect of P4 Ser phosphorylation, phosphorylation of P1 Tyr prevented substrate hydrolysis by HIV-1 proteinase. Substrate phosphorylation had substantially smaller effects on the hydrolysis by the avian retroviral proteinase. As the active retroviral proteinase as well as various protein kinases are incorporated into mature virions, substrate phosphorylation resulting in attenuation or prevention of proteolytic processing may have important consequences in the regulation of the retroviral life cycle as well as in virus-host cell interactions.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:European Journal Of Biochemistry. - 265 : 1 (1999), p. 423-429. -
További szerzők:Bagossi Péter (1966-2011) (biokémikus, vegyész) Boross Péter (1972-) (biokémikus, vegyész) Louis, John M. Majerova, Eva Oroszlan, Stephen Copeland, Terry D.
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5.

001-es BibID:BIBFORM040126
Első szerző:Tőzsér József (molekuláris biológus, biokémikus, vegyész)
Cím:Comparison of the substrate specificity of the human T-cell leukemia virus and human immunodeficiency virus proteinases / József Tőzsér, Gábor Zahuczky, Péter Bagossi, John M. Louis, Terry D. Copeland, Stephen Oroszlan, Robert W. Harrison, Irene T. Weber
Dátum:2000
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:European Journal of Biochemistry. - 267 : 20 (2000), p. 6287-6295. -
További szerzők:Zahuczky Gábor (1975-) (molekuláris biológus, biokémikus, vegyész) Bagossi Péter (1966-2011) (biokémikus, vegyész) Louis, John M. Copeland, Terry D. Oroszlan, Stephen Harrison, Robert W. Weber, Irene T.
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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