[Figure: see text].
- MeSH
- adaptorové proteiny signální transdukční chemie metabolismus MeSH
- DNA vazebné proteiny chemie metabolismus MeSH
- elongace genetické transkripce * MeSH
- exprese genu MeSH
- interakční proteinové domény a motivy genetika MeSH
- lidé MeSH
- mapy interakcí proteinů MeSH
- molekulární modely MeSH
- mutace MeSH
- nádorové buněčné linie MeSH
- proteinové domény MeSH
- proteiny vázající RNA chemie genetika metabolismus MeSH
- RNA-polymerasa II chemie metabolismus MeSH
- transkripční elongační faktory chemie metabolismus MeSH
- transkripční faktory chemie genetika metabolismus MeSH
- vazba proteinů MeSH
- vnitřně neuspořádané proteiny chemie metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Dimerization of many eukaryotic transcription regulatory factors is critical for their function. Regulatory role of an epigenetic reader lens epithelium-derived growth factor/p75 (LEDGF/p75) requires at least two copies of this protein to overcome the nucleosome-induced barrier to transcription elongation. Moreover, various LEDGF/p75 binding partners are enriched for dimeric features, further underscoring the functional regulatory role of LEDGF/p75 dimerization. Here, we dissected the minimal dimerization region in the C-terminal part of LEDGF/p75 and, using paramagnetic NMR spectroscopy, identified the key molecular contacts that helped to refine the solution structure of the dimer. The LEDGF/p75 dimeric assembly is stabilized by domain swapping within the integrase binding domain and additional electrostatic "stapling" of the negatively charged α helix formed in the intrinsically disordered C-terminal region. We validated the dimerization mechanism using structure-inspired dimerization defective LEDGF/p75 variants and chemical crosslinking coupled to mass spectrometry. We also show how dimerization might affect the LEDGF/p75 interactome.
Lens epithelium-derived growth factor (LEDGF/p75) is an epigenetic reader and attractive therapeutic target involved in HIV integration and the development of mixed lineage leukaemia (MLL1) fusion-driven leukaemia. Besides HIV integrase and the MLL1-menin complex, LEDGF/p75 interacts with various cellular proteins via its integrase binding domain (IBD). Here we present structural characterization of IBD interactions with transcriptional repressor JPO2 and domesticated transposase PogZ, and show that the PogZ interaction is nearly identical to the interaction of LEDGF/p75 with MLL1. The interaction with the IBD is maintained by an intrinsically disordered IBD-binding motif (IBM) common to all known cellular partners of LEDGF/p75. In addition, based on IBM conservation, we identify and validate IWS1 as a novel LEDGF/p75 interaction partner. Our results also reveal how HIV integrase efficiently displaces cellular binding partners from LEDGF/p75. Finally, the similar binding modes of LEDGF/p75 interaction partners represent a new challenge for the development of selective interaction inhibitors.
- MeSH
- dimerizace MeSH
- Escherichia coli MeSH
- histonlysin-N-methyltransferasa metabolismus MeSH
- HIV-integrasa metabolismus MeSH
- konsenzuální sekvence MeSH
- Lentivirus enzymologie MeSH
- lidé MeSH
- mezibuněčné signální peptidy a proteiny metabolismus MeSH
- molekulární sekvence - údaje MeSH
- proteiny metabolismus MeSH
- protoonkogenní protein MLL metabolismus MeSH
- represorové proteiny metabolismus MeSH
- sekvence aminokyselin MeSH
- terciární struktura proteinů MeSH
- transposasy metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Specific antibodies interfere with the function of human tumor-associated carbonic anhydrase IX (CA IX), and show potential as tools for anticancer interventions. In this work, a correlation between structural elements and thermodynamic parameters of the association of antibody fragment Fab M75 to a peptide corresponding to its epitope in the proteoglycan-like domain of CA IX, is presented. Comparisons of the crystal structures of free Fab M75 and its complex with the epitope peptide reveal major readjustments of CDR-H1 and CDR-H3. In contrast, the overall conformations and positions of CDR-H2 and CDR-L2 remain unaltered, and their positively charged residues may thus present a fixed frame for epitope recognition. Adoption of the altered CDR-H3 conformation in the structure of the complex is accompanied by an apparent local stabilization. Analysis of domain mobility with translation-libration-screw (TLS) method shows that librations of the entire heavy chain variable domain (V(H)) decrease and reorient in the complex, which correlates well with participation of the heavy chain in ligand binding. Isothermal titration microcalorimetry (ITC) experiments revealed a highly unfavorable entropy term, which can be attributed mainly to the decrease in the degrees of freedom of the system, the loss of conformational freedom of peptide and partially to a local stabilization of CDR-H3. Moreover, it was observed that one proton is transferred from the environment to the protein-ligand complex upon binding. Molecular dynamics simulations followed by molecular mechanics/generalized Born surface area (MM-GBSA) calculations of the ligand (epitope peptide) binding energy yielded energy values that were in agreement with the ITC measurements and indicated that the charged residues play crucial role in the epitope binding. Theoretical arguments presented in this work indicate that two adjacent arginine residues (ArgH50 and ArgH52) are responsible for the observed proton transfer. 2007 Wiley-Liss, Inc.
- MeSH
- antigeny nádorové chemie imunologie MeSH
- epitopy chemie imunologie MeSH
- financování organizované MeSH
- imunoglobuliny - Fab fragmenty chemie MeSH
- izoenzymy chemie imunologie MeSH
- kalorimetrie MeSH
- karboanhydrasy chemie imunologie MeSH
- krystalografie rentgenová MeSH
- lidé MeSH
- molekulární sekvence - údaje MeSH
- monoklonální protilátky chemie MeSH
- nádorové buněčné linie MeSH
- počítačová simulace MeSH
- sekvence aminokyselin MeSH
- termodynamika MeSH
- vazebná místa protilátek MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- srovnávací studie MeSH
The monoclonal antibodies 1696 and F11.2.32 strongly inhibit the activity of wild-type HIV-1 protease (PR) by binding to epitopes at the enzyme N-terminus (residues 1-6) and flap residues 36-46, respectively. Here we demonstrate that these antibodies are also potent inhibitors of PR variants resistant to active-site inhibitors used as anti-AIDS drugs. Our in vitro experiments revealed that the inhibitory potency of single-chain fragments (scFv) of these antibodies is not significantly affected by the presence of mutations in PR; inhibition constants for drug-resistant protease variants are 5-11 nM and 13-169 nM for scFv1696 and for scFvF11.2.32, respectively. Tethered dimer of HIV-1 PR variant proved to be a model protease variant resistant to dissociative inhibition by 1696, and, strikingly, it also displayed resistance to inhibition by F11.2.32 suggesting that dimer dissociation also plays a role in the inhibitory action of F11.2.32.
- MeSH
- dimerizace MeSH
- financování organizované MeSH
- genetická variace MeSH
- HIV infekce farmakoterapie virologie MeSH
- HIV-1 enzymologie genetika účinky léků MeSH
- HIV-proteasa genetika imunologie účinky léků MeSH
- imunoglobuliny - fragmenty farmakologie imunologie MeSH
- inhibitory HIV-proteasy farmakologie MeSH
- lidé MeSH
- molekulární modely MeSH
- monoklonální protilátky farmakologie imunologie MeSH
- mutace MeSH
- rekombinantní proteiny farmakologie imunologie MeSH
- virová léková rezistence genetika MeSH
- vysoce aktivní antiretrovirová terapie MeSH
- Check Tag
- lidé MeSH
- MeSH
- aspartátové endopeptidasy genetika chemie imunologie MeSH
- finanční podpora výzkumu jako téma MeSH
- HIV protilátky chemie imunologie MeSH
- HIV-proteasa imunologie MeSH
- lidé MeSH
- monoklonální protilátky chemie MeSH
- peptidy chemie imunologie MeSH
- sekvence aminokyselin MeSH
- zkřížené reakce MeSH
- Check Tag
- lidé MeSH
BACKGROUND: The aim of the study was to determine pregnancy-associated plasma protein-A (PAPP-A), which was recently described as a new marker of cardiovascular events, in patients with chronic renal insufficiency/failure and to find out its relationship to renal function and to prominent markers of oxidative stress (advanced oxidation protein products--AOPP) and inflammation (C-reactive protein--CRP). METHODS: The studied group consisted of 36 chronic hemodialysis patients (HD), 10 patients treated with continuous ambulatory peritoneal dialysis (CAPD) and 38 patients with chronic renal insufficiency (CHRI) not yet dialyzed. PAPP-A was measured by Time Resolved Amplified Cryptate Emission technology. Determination of AOPP is based on a spectrophotometric method. RESULTS: PAPP-A levels are statistically significantly elevated in the both groups of dialyzed patients in comparison with healthy subjects (27.0 +/- 16.5 mIU/l in HD and 14.07 +/- 6.73 mIU/l in CAPD vs. 8.22 +/- 2.7 mIU/l in the control group, p < 0.0001 and p < 0.001, respectively, p < 0.05 HD vs. CAPD). The mean serum PAPP-A levels in the CHRI patients not yet dialyzed were not significantly higher in comparison with the control group (9.72 +/-4.44 vs. 8.22 +/- 2.7 mIU/l, n.s.). In the CHRI not dialyzed patients, we found a significant positive correlation between serum creatinine and PAPP-A levels (r = 0.68, p < 0.05). In comparison with controls, AOPP and CRP levels were significantly higher in HD patients [AOPP 155.0 +/- 37.9 micromol/l, p < 0.0001 vs. controls, CRP 10.0 (4.6- 26.9) mg/l (median, interquartile range), p < 0.0001 vs. controls], CAPD patients [AOPP 118.5 +/- 25.8 micromol/l, p < 0.0001 vs. controls, CRP 7.7 (2.0-18.8) mg/l, p < 0.01 vs. controls] and AOPP levels in chronic renal failure patients not yet dialyzed (98.5 +/- 43.24 micromol/l, p < 0.01 vs. controls). The correlations between PAPP-A and AOPP (r = 0.49, p < 0.05) and PAPP-A and CRP (r = 0.48, p < 0.05) serum concentration were statistically significant in HD patients. In CAPD patients, neither a correlation between PAPP-A and AOPP nor a correlation between PAPP-A and CRP were found. CONCLUSION: We can conclude that serum PAPP-A levels sensitively reflect the changes in renal function, depend on dialysis modality, and may represent a novel marker associated with inflammation and oxidative stress in chronic renal failure patients. Copyright 2004 S. Karger AG, Basel
- MeSH
- biologické markery krev MeSH
- C-reaktivní protein metabolismus MeSH
- chronické selhání ledvin krev patofyziologie terapie MeSH
- dialýza ledvin MeSH
- kontinuální ambulantní peritoneální dialýza MeSH
- krevní proteiny MeSH
- ledviny patofyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- oxidační stres MeSH
- senioři MeSH
- stupeň závažnosti nemoci MeSH
- těhotenský plazmatický protein A metabolismus MeSH
- zánět krev MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- abstrakt z konference MeSH
