Secreted aspartic proteases (Saps) of pathogenic Candida spp. represent a specific target for antifungal drug development. We synthesized a series of peptidomimetic inhibitors with different isosteric groups and modifications at individual positions and tested them with purified Saps from C. albicans (Sap2p), C. tropicalis (Sapt1p), and C. parapsilosis (Sapp1p). The kinetic parameters indicated that all three proteases prefer binding of inhibitors containing bulky hydrophobic residues between positions P3 and P3'. The most divergent specificity was found for Sapp1p. The sequence alignment of Sap2p, Sapt1p, and Sapp1p, and homology modeling of Sapp1p with the crystal structure of Sapt1p and the complex of Sap2p with a peptidomimetic inhibitor showed that the overall folds of Sap2p, Sapt1p, and Sapp1p are similar. However, the N- and C-terminal loops formed by disulfide bonds between residues 47-53 and 258-292 are significantly shorter in Sapp1p, and a unique insertion following Tyr 129 in Sapp1p results in the formation of a loop that can interact with inhibitor residues. These Sapp1p structural differences might lead to its altered susceptibility to inhibition.
- MeSH
- aspartátové endopeptidasy chemie účinky léků MeSH
- Candida enzymologie MeSH
- financování organizované MeSH
- inhibitory proteas farmakologie chemická syntéza chemie MeSH
- izoenzymy chemie účinky léků MeSH
- molekulární konformace MeSH
- molekulární modely MeSH
- molekulární sekvence - údaje MeSH
- sekvence aminokyselin MeSH
- sekvenční homologie aminokyselin MeSH
- stereoizomerie MeSH
- substrátová specifita MeSH
- terciární struktura proteinů MeSH
- vztahy mezi strukturou a aktivitou MeSH
The specificity of the proteinase of myeloblastosis-associated virus (MAV) was studied with (a) 21 substrate-based inhibitors, (b) 9 inhibitors with pseudopalindrome sequences, (c) 8 chimeric inhibitors, and (d) 3 compounds designed as human immunodeficiency virus 1 (HIV-1) proteinase inhibitors. The central inhibitory unit (transition state or cleaved bond analog) and the role of the inhibitor side chains from P4 to P4' were investigated. MAV proteinase prefers an aromatic side chain in P1 and a small aliphatic nonpolar chain in P2 and P2'. Residues in P5 and P4 positions are outside of the short catalytic cleft of the enzyme, but still influence binding considerably. The data obtained provide evidence that the MAV proteinase has generally lower specificity and poorer binding than the HIV proteinase.
- MeSH
- aspartátové endopeptidasy * antagonisté a inhibitory MeSH
- HIV-1 enzymologie MeSH
- HIV-proteasa metabolismus MeSH
- inhibitory proteas farmakologie chemická syntéza MeSH
- kinetika MeSH
- molekulární sekvence - údaje MeSH
- oligopeptidy farmakologie chemická syntéza MeSH
- sekvence aminokyselin MeSH
- substrátová specifita MeSH
- virus ptačí myeloblastózy * enzymologie MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- srovnávací studie MeSH
- MeSH
- aspartátové endopeptidasy genetika metabolismus MeSH
- HIV-proteasa metabolismus MeSH
- kinetika MeSH
- molekulární sekvence - údaje MeSH
- mutageneze cílená MeSH
- oligopeptidy chemie MeSH
- proteinové inženýrství MeSH
- sekvence aminokyselin MeSH
- substrátová specifita MeSH
- virus ptačí myeloblastózy * enzymologie genetika MeSH
