Inhibition of tryptase TL2 from human T4+ lymphocytes and inhibition of HIV1 replication in h9 cells by recombinant aprotinin and bikunin homologues

Thomas Brinkmann, Jochen Schäfers, Lutz Gürtler, Hiroshi Kido, Yasuharu Niwa, Nobuhiko Katunuma, Harald Tschesche

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

The serine esterase TL2 from human T4+ lymphocytes is a binding component to HIV-1 glycoprotein gp120 and seems to play a role in the HIV-1 infection mechanism. Recombinant variants of the Kunitz-type serine proteinase inhibitor aprotinin were investigated for their ability to inhibit tryptase TL2 and the binding of gp120 to this enzyme. Furthermore, the viral replication of HIV-1 was investigated in H9 cell cultures under the influence of recombinant aprotinin and bikunin variants. In contrast to native aprotinin, the recombinant variant [Arg15, Phe17, Glu52]aprotinin with a reactive-site sequence homologous to the V3 loop of HIV4 gp120 showed a specific inhibition of tryptase TL2 (>80%). However, the [Leu15 Phe17, Glu52]aprotinin variant with hydrophohie subsites was the most potent inhibitor of the binding of gp120 to tryptase TL2 (68%). Our results show that the enzyme activity of purified tryptase TL2 is inhibited not only by variants with basic amino acids, but also those with hydrophobic residues in the reactive-site region. Therefore, tryptase TL2 is not a typical trypsin- like or chymotrypsinlike protease. Investigations on inhibition of HIV-1 replication in H9 cell cultures showed that tryptase TL2 is involved in the mechanism of virus internalization into human lymphocytes. The [Leu15, Phe17, Glu52]aprotinin showed a significant retardation of syncytium formation over a period of 5 days in a 1 μM concentration. Similar investigations were performed with recombinant variants of bikunin, the light chain of human inter-α-trypsin inhibitor. Only the single-headed variant [Arg94](δ2) bikunin inhibited slightly the syncytium formation over a period of 2 days in a 2.2μM concentration. Wild-type bikunin and all full- length variants showed no effect, possibly due to steric hindrance by the second domain of the double-headed inhibitor.

Original languageEnglish
Pages (from-to)651-660
Number of pages10
JournalJournal of Protein Chemistry
Volume16
Issue number6
DOIs
Publication statusPublished - 08-1997
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biochemistry

Fingerprint

Dive into the research topics of 'Inhibition of tryptase TL<sub>2</sub> from human T4<sup>+</sup> lymphocytes and inhibition of HIV1 replication in h9 cells by recombinant aprotinin and bikunin homologues'. Together they form a unique fingerprint.

Cite this