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Portability of a Small-Molecule Binding Site between Disordered Proteins. Biomolecules 2022; 12:biom12121887. [PMID: 36551315 PMCID: PMC9775153 DOI: 10.3390/biom12121887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 12/07/2022] [Accepted: 12/09/2022] [Indexed: 12/23/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) are important in both normal and disease states. Small molecules can be targeted to disordered regions, but we currently have only a limited understanding of the nature of small-molecule binding sites in IDPs. Here, we show that a minimal small-molecule binding sequence of eight contiguous residues derived from the Myc protein can be ported into a different disordered protein and recapitulate small-molecule binding activity in the new context. We also find that the residue immediately flanking the binding site can have opposing effects on small-molecule binding in the different disordered protein contexts. The results demonstrate that small-molecule binding sites can act modularly and are portable between disordered protein contexts but that residues outside of the minimal binding site can modulate binding affinity.
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Vignoli Muniz GS, Souza MC, Duarte EL, Lamy MT. Comparing the interaction of the antibiotic levofloxacin with zwitterionic and anionic membranes: Calorimetry, fluorescence, and spin label studies. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183622. [PMID: 33865809 DOI: 10.1016/j.bbamem.2021.183622] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/30/2021] [Accepted: 03/31/2021] [Indexed: 11/30/2022]
Abstract
The present work compares the interaction of the antibiotic levofloxacin (LVX) with zwitterionic and anionic liposomes composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DPPG), respectively. By using differential scanning calorimetry (DSC), and with spin labels incorporated into liposomes at two different depths of the bilayers, we investigated the changes induced on the membrane by increasing concentrations of LVX. Further information was obtained using intrinsic LVX fluorescence. Under the conditions used here, all techniques evinced that LVX has little affinity for DPPC zwitterionic membrane. Opposite to that, LVX exhibits a considerable affinity for anionic bilayers, with membrane partition constants Kp = (3.3 ± 0.5) × 102 and (4.5 ± 0.3) × 102, for gel and fluid DPPG membranes, respectively. On binding to DPPG, LVX seems to give rise to the coexistence of LVX -rich and -poor domains on DPPG membranes, as detected by DSC. At the highest LVX concentration used (20 mol%), DSC trace shows an increase in the cooperativity of DPPG gel-fluid transition, also detected by spin labels as an increase in the bilayer packing. Moreover, LVX does not induce pore formation in either DPPG or POPG vesicles. Considering the possible relevance of LVX-membrane interaction for the biological and toxicological action of the antibiotic, the findings discussed here certainly contribute to a better understanding of its action, and the planning of new drugs.
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Affiliation(s)
| | - Mariana C Souza
- Instituto de Física, Universidade de São Paulo, São Paulo, SP CEP 05508-090, Brazil
| | - Evandro L Duarte
- Instituto de Física, Universidade de São Paulo, São Paulo, SP CEP 05508-090, Brazil
| | - M Teresa Lamy
- Instituto de Física, Universidade de São Paulo, São Paulo, SP CEP 05508-090, Brazil.
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Jung SH, Kim KY, Lee JH, Moon CJ, Han NS, Park SJ, Kang D, Song JK, Lee SS, Choi MY, Jaworski J, Jung JH. Self-Assembled Tb 3+ Complex Probe for Quantitative Analysis of ATP during Its Enzymatic Hydrolysis via Time-Resolved Luminescence in Vitro and in Vivo. ACS APPLIED MATERIALS & INTERFACES 2017; 9:722-729. [PMID: 27935287 DOI: 10.1021/acsami.6b12857] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
To more accurately assess the pathways of biological systems, a probe is needed that may respond selectively to adenosine triphosphate (ATP) for both in vitro and in vivo detection modes. We have developed a luminescence probe that can provide real-time information on the extent of ATP, ADP, and AMP by virtue of the luminescence and luminescence lifetime observed from a supramolecular polymer based on a C3 symmetrical terpyridine complex with Tb3+ (S1-Tb). The probe shows remarkable selective luminescence enhancement in the presence of ATP compared to other phosphate-displaying nucleotides including adenosine diphosphate (ADP), adenosine monophosphate (AMP), guanosine triphosphate (GTP), thymidine triphosphate (TTP), H2PO4- (Pi), and pyrophosphate (PPi). In addition, the time-resolved luminescence lifetime and luminescence spectrum of S1-Tb could facilitate the quantitative measurement of the exact amount of ATP and similarly ADP and AMP within living cells. The time-resolved luminescence lifetime of S1-Tb could also be used to quantitatively monitor the amount of ATP, ADP, and AMP in vitro following the enzymatic hydrolysis of ATP. The long luminescence lifetime, which was observed into the millisecond range, makes this S1-Tb-based probe particularly attractive for monitoring biological ATP levels in vivo, because any short lifetime background fluorescence arising from the complex molecular environment may be easily eliminated.
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Affiliation(s)
- Sung Ho Jung
- Department of Chemistry and Research Institute of Natural Sciences, Gyeongsang National University , Jinju, Korea
| | - Ka Young Kim
- Department of Chemistry and Research Institute of Natural Sciences, Gyeongsang National University , Jinju, Korea
| | - Ji Ha Lee
- Department of Chemistry and Research Institute of Natural Sciences, Gyeongsang National University , Jinju, Korea
| | - Cheol Joo Moon
- Department of Chemistry and Research Institute of Natural Sciences, Gyeongsang National University , Jinju, Korea
| | - Noh Soo Han
- Department of Chemistry, Kyung Hee University , Seoul 130-701, Korea
| | - Su-Jin Park
- Department of Life Science, Ewha Womans University , Seoul 120-750, Korea
| | - Dongmin Kang
- Department of Life Science, Ewha Womans University , Seoul 120-750, Korea
| | - Jae Kyu Song
- Department of Chemistry, Kyung Hee University , Seoul 130-701, Korea
| | - Shim Sung Lee
- Department of Chemistry and Research Institute of Natural Sciences, Gyeongsang National University , Jinju, Korea
| | - Myong Yong Choi
- Department of Chemistry and Research Institute of Natural Sciences, Gyeongsang National University , Jinju, Korea
| | - Justyn Jaworski
- Department of Chemical Engineering and Institute of Nanoscience and Technology, Hanyang University , Seoul, Korea
| | - Jong Hwa Jung
- Department of Chemistry and Research Institute of Natural Sciences, Gyeongsang National University , Jinju, Korea
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Draffehn S, Kumke MU. Monitoring the Collapse of pH-Sensitive Liposomal Nanocarriers and Environmental pH Simultaneously: A Fluorescence-Based Approach. Mol Pharm 2016; 13:1608-17. [PMID: 27050158 DOI: 10.1021/acs.molpharmaceut.6b00064] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Nowadays, the encapsulation of therapeutic compounds in so-called carrier systems is a very smart method to achieve protection as well as an improvement of their temporal and spatial distribution. After the successful transport to the point of care, the delivery has to be released under controlled conditions. To monitor the triggered release from the carrier, we investigated different fluorescent probes regarding their response to the pH-induced collapse of pH-sensitive liposomes (pHSLip), which occurs when the environmental pH falls below a critical value. Depending on the probe, the fluorescence decay time as well as fluorescence anisotropy can be used equally as key parameters for monitoring the collapse. Especially the application of a fluorescein labeled fatty acid (fPA) enabled the monitoring of the pHSLips collapse and the pH of its microenvironment simultaneously without interference. Varying the pH in the range of 3 < pH < 9, anisotropy data revealed the critical pH value at which the collapse of the pHSLips occurs. Complementary methods, e.g., fluorescence correlation spectroscopy and dynamic light scattering, supported the analysis based on the decay time and anisotropy. Additional experiments with varying incubation times yielded information on the kinetics of the liposomal collapse.
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Affiliation(s)
- Sören Draffehn
- Physical Chemistry, Institute of Chemistry, University of Potsdam , Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
| | - Michael U Kumke
- Physical Chemistry, Institute of Chemistry, University of Potsdam , Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
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