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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:BIBFORM040659
Első szerző:Fenyőfalvi György
Cím:Expression and characterization of human foamy virus proteinase / Fenyöfalvi György, Bagossi Péter, Copeland Terry D., Oroszlan Stephen, Boross Péter, Tözsér József
Dátum:1999
ISSN:0014-5793
Megjegyzések:The human foamy virus proteinase was expressed in fusion with maltose binding protein in Escherichia coli and purified. The specific activity of the fusion protein was similar to that of the processed enzyme. The kinetic constants on foamy virus cleavage site substrates were very low but comparable to those obtained with the gag-encoded avian proteinase on its own substrates. The proteinase showed preference for high ionic strength and a pH optimum of 6.6. None of the tested retroviral cleavage site peptides were substrates, however, some peptides representing cleavage sites in retrotransposons were properly processed by the enzyme
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Febs Letters. - 462 : 3 (1999), p. 397-401. -
További szerzők:Bagossi Péter (1966-2011) (biokémikus, vegyész) Copeland, Terry D. Oroszlan, Stephen Boross Péter (1972-) (biokémikus, vegyész) Tőzsér József (1959-) (molekuláris biológus, biokémikus, vegyész)
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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:BIBFORM040704
Első szerző:Tőzsér József (molekuláris biológus, biokémikus, vegyész)
Cím:Human immunodeficiency virus type 1 capsid protein is a substrate of the retroviral proteinase while integrase is resistant toward proteolysis / Tözsér József, Shulenin Sergey, Kádas János, Boross Péter, Bagossi Péter, Copeland Terry D., Nair Bala C., Sarngadharan Mangalasseril G., Oroszlan Stephen
Dátum:2003
ISSN:0042-6822
Megjegyzések:The capsid protein of human immunodeficiency virus type 1 was observed to undergo proteolytic cleavage in vitro when viral lysate was incubated in the presence of dithiothreitol at acidic pH. Purified HIV-1 capsid protein was also found to be a substrate of the viral proteinase in a pH-dependent manner; acidic pH (<7) was necessary for cleavage, and decreasing the pH toward 4 increased the degree of processing. Based on N-terminal sequencing of the cleavage products, the capsid protein was found to be cleaved at two sites, between residues 77 and 78 as well as between residues 189 and 190. Oligopeptides representing these cleavage sites were also cleaved at the expected peptide bonds. The presence of cyclophilin A decreased the degree of capsid protein processing. Unlike the capsid protein, integrase was found to be resistant toward proteolysis in good agreement with its presence in the preintegration complex.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Virology. - 310 : 1 (2003), p. 16-23. -
További szerzők:Shulenin, Sergey Kádas János (1976-) (molekuláris biológus, biokémikus, kertészmérnök) Boross Péter (1972-) (biokémikus, vegyész) Bagossi Péter (1966-2011) (biokémikus, vegyész) Copeland, Terry D. Nair, Bala C. Sarngadharan, Mangalasseril G. Oroszlan, Stephen
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6.

001-es BibID:BIBFORM039225
Első szerző:Zahuczky Gábor (molekuláris biológus, biokémikus, vegyész)
Cím:Cloning of the bovine leukemia virus proteinase in Escherichia coli and comparison of its specificity to that of human T-cell leukemia virus proteinase / Gábor Zahuczky, Péter Boross, Péter Bagossi, Gabriella Emri, Terry D. Copeland, Stephen Oroszlan, John M. Louis, József Tőzsér
Dátum:2000
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Biochimica et Biophysica Acta (BBA). Protein Structure and Molecular Enzymology. - 1478 : 1 (2000), p. 1-8. -
További szerzők:Boross Péter (1972-) (biokémikus, vegyész) Bagossi Péter (1966-2011) (biokémikus, vegyész) Emri Gabriella (1972-) (bőrgyógyász, allergológus, onkológus) Copeland, Terry D. Oroszlan, Stephen Louis, John M. Tőzsér József (1959-) (molekuláris biológus, biokémikus, vegyész)
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