scholarly journals Identification and mechanistic analysis of an inhibitor of the CorC Mg2+ transporter

2021 ◽  
Author(s):  
Yichen Huang ◽  
Kaijie Mu ◽  
Xinyu Teng ◽  
Yimeng Zhao ◽  
Yosuke Funato ◽  
...  
Keyword(s):  
Binding Site ◽  
Transmembrane Domain ◽  
Chemical Compounds ◽  
Cytoplasmic Domain ◽  
Structural Basis ◽  
Atp Binding ◽  
Inhibitory Effects ◽  
Atp Binding Site ◽  
Design And Optimization ◽  
Mechanistic Analysis

AbstractThe CorC/CNNM family of Na+-dependent Mg2+ transporters is ubiquitously conserved from bacteria to humans. CorC, the bacterial member of the CorC/CNNM family of proteins, is involved in resistance to antibiotic exposure and in the survival of pathogenic microorganisms in their host environment. The CorC/CNNM family proteins possess a cytoplasmic region containing the regulatory ATP-binding site. While CorC and CNNM have attracted interest as therapeutic targets, inhibitors targeting the ir regulatory ATP-binding site have not yet been identified.Here, we performed a virtual screening of CorC by targeting its regulatory ATP-binding site, identified a chemical compound named IGN95a with inhibitory effects on both ATP binding and Mg2+ export, and determined the cytoplasmic domain structure in complex with IGN95a. Furthermore, a chemical cross-linking experiment indicated that with ATP bound to the cytoplasmic domain, the conformational equilibrium of CorC was shifted more towards the inward-facing state of the transmembrane domain. In contrast, IGN95a did not induce such a shift. Our results provide a structural basis for the further design and optimization of chemical compounds targeting the regulatory ATP-binding site of CorC as well as mechanistic insights into how ATP and chemical compounds modulate the transport activity of CorC.

Fluorometric study on conformational changes in the catalytic cycle of sarcoplasmic reticulum Ca2+-ATPase

1995 ◽  
Vol 15 (5) ◽  
pp. 317-326 ◽  
Author(s):  
Tohru Kanazawa ◽  
Hiroshi Suzuki ◽  
Takashi Daiho ◽  
Kazuo Yamasaki
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Binding Site ◽  
Conformational Changes ◽  
Binding Sites ◽  
Transmembrane Domain ◽  
Tryptophan Fluorescence ◽  
Cytoplasmic Domain ◽  
Catalytic Cycle ◽  
Atp Binding ◽  
Atp Binding Site

Changes in the fluoresence of N-acetyl-N′-(5-sulfo-1-naphthyl)ethylenediamine (EDANS), being attached to Cys-674 of sarcoplasmic reticulum Ca2+-ATPase without affecting the catalytic activity, as well as changes in the intrinsic tryptophan fluorescence were followed throughout the catalytic cycle by the steady-state measurements and the stopped-flow spectrofluorometry. EDANS-fluorescence changes reflect conformational changes near the ATP binding site in the cytoplasmic domain, while tryptophan-fluorescence changes most probably reflect conformational changes in or near the transmembrane domain in which the Ca2+ binding sites are located. Formation of the phosphoenzyme intermediates (EP) was also followed by the continuous flow-rapid quenching method. The kinetic analysis of EDANS-fluorescence changes and EP formation revealed that, when ATP is added to the calcium-activated enzyme, conformational changes in the ATP binding site occur in three successive reaction steps; conformational change in the calcium enzyme substrate complex, formation of ADP-sensitive EP, and transition of ADP-sensitive EP to ADP-insensitive EP. In contrast, the ATP-induced tryptophan-fluorescence changes occur only in the latter two steps. Thus, we conclude that conformational changes in the ATP binding site in the cytoplasmic domain are transmitted to the Ca2+-binding sites in the transmembrane domain in these latter two steps.

Structural basis for tailor-made selective PI3K α/β inhibitors: a computational perspective

2021 ◽  
Vol 45 (1) ◽  
pp. 373-382
Author(s):  
Huibin Wang ◽  
Ying Wang ◽  
Chunshi Li ◽  
Hanxun Wang ◽  
Xiaohui Geng ◽  
...  
Keyword(s):  
Binding Site ◽  
Structural Basis ◽  
Atp Binding ◽  
Atp Binding Site ◽  
Computational Perspective

PI3K α and β are Class IA PI3K isoforms that share a highly homologous ATP binding site, differing only in a few residues around the binding site.

scholarly journals Localization of the ATP/Phosphatidylinositol 4,5 Diphosphate-binding Site to a 39-Amino Acid Region of the Carboxyl Terminus of the ATP-regulated K+Channel Kir1.1

2002 ◽  
Vol 277 (51) ◽  
pp. 49366-49373 ◽  
Author(s):  
Ke Dong ◽  
LieQi Tang ◽  
Gordon G. MacGregor ◽  
Steven C. Hebert
Keyword(s):  
Amino Acid ◽  
Binding Site ◽  
Transmembrane Domain ◽  
Direct Interaction ◽  
Terminal Segment ◽  
K Channel ◽  
Atp Binding ◽  
Amino Acid Residues ◽  
Atp Binding Site ◽  
Arginine Residues

Intracellular ATP and membrane-associated phosphatidylinositol phospholipids, like PIP2(PI(4,5)P2), regulate the activity of ATP-sensitive K+(KATP) and Kir1.1 channels by direct interaction with the pore-forming subunits of these channels. We previously demonstrated direct binding of TNP-ATP (2′,3′-O-(2,4,6-trinitrophenylcyclo-hexadienylidene)-ATP) to the COOH-terminal cytosolic domains of the pore-forming subunits of Kir1.1 and Kir6.x channels. In addition, PIP2competed for TNP-ATP binding on the COOH termini of Kir1.1 and Kir6.x channels, providing a mechanism that can account for PIP2antagonism of ATP inhibition of these channels. To localize the ATP-binding site within the COOH terminus of Kir1.1, we produced and purified maltose-binding protein (MBP) fusion proteins containing truncated and/or mutated Kir1.1 COOH termini and examined the binding of TNP-ATP and competition by PIP2. A truncated COOH-terminal fusion protein construct, MBP_1.1CΔC170, containing the first 39 amino acid residues distal to the second transmembrane domain was sufficient to bind TNP-ATP with high affinity. A construct containing the remaining COOH-terminal segment distal to the first 39 amino acid residues did not bind TNP-ATP. Deletion of 5 or more amino acid residues from the NH2-terminal side of the COOH terminus abolished nucleotide binding to the entire COOH terminus or to the first 49 amino acid residues of the COOH terminus. PIP2competed TNP-ATP binding to MBP_1.1CΔC170 with an EC50of 10.9 μm. Mutation of any one of three arginine residues (R188A/E, R203A, and R217A), which are conserved in Kir1.1 and KATPchannels and are involved in ATP and/or PIP2effects on channel activity, dramatically reduced TNP-ATP binding to MBP_1.1ΔC170. In contrast, mutation of a fourth conserved residue (R212A) exhibited slightly enhanced TNP-ATP binding and increased affinity for PIP2competition of TNP-ATP (EC50= 5.7 μm). These studies suggest that the first 39 COOH-terminal amino acid residues form an ATP-PIP2binding domain in Kir1.1 and possibly the Kir6.x ATP-sensitive K+channels.

scholarly journals Discovery of COVID-19 Inhibitors Targeting the SARS-CoV2 Nsp13 Helicase

2020 ◽  
Author(s):  
Mark Andrew White ◽  
Wei Lin ◽  
Xiaodong Cheng
Keyword(s):  
Molecular Dynamics ◽  
Binding Site ◽  
Structural Models ◽  
Chemical Compounds ◽  
Atp Binding ◽  
Significant Activity ◽  
Structural Protein ◽  
Atp Binding Site ◽  
Potential Inhibitors ◽  
Effective Drugs

ABSTRACTThe raging COVID-19 pandemic caused by SARS-CoV2 has infected millions of people and killed several hundred thousand patients worldwide. Currently, there are no effective drugs or vaccines available for treating coronavirus infections. In this study, we have focused on the SARS-CoV2 helicase (Nsp13), which is critical for viral replication and the most conserved non-structural protein within the coronavirus family. Using homology modeling and molecular dynamics approaches, we generated structural models of the SARS-CoV2 helicase in its apo- and ATP/RNA-bound conformations. We performed virtual screening of ~970,000 chemical compounds against the ATP binding site to identify potential inhibitors. Herein, we report docking hits of approved human drugs targeting the ATP binding site. Importantly, two of our top drug hits have significant activity in inhibiting purified recombinant SARS-CoV-2 helicase, providing hope that these drugs can be potentially repurposed for the treatment of COVID-19.

New Mechanistic Insight on the PIM-1 Kinase Inhibitor AZD1208 Using Multidrug Resistant Human Erythroleukemia Cell Lines and Molecular Docking Simulations

2019 ◽  
Vol 19 (11) ◽  
pp. 914-926 ◽  
Author(s):  
Maiara Bernardes Marques ◽  
Michael González-Durruthy ◽  
Bruna Félix da Silva Nornberg ◽  
Bruno Rodrigues Oliveira ◽  
Daniela Volcan Almeida ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Binding Site ◽  
Cell Lines ◽  
Chemotherapeutic Agents ◽  
Atp Binding ◽  
Human Leukemia ◽  
Atp Binding Site ◽  
Mechanistic Insight ◽  
Multiple Drugs

Background:PIM-1 is a kinase which has been related to the oncogenic processes like cell survival, proliferation, and multidrug resistance (MDR). This kinase is known for its ability to phosphorylate the main extrusion pump (ABCB1) related to the MDR phenotype.Objective:In the present work, we tested a new mechanistic insight on the AZD1208 (PIM-1 specific inhibitor) under interaction with chemotherapy agents such as Daunorubicin (DNR) and Vincristine (VCR).Materials and Methods:In order to verify a potential cytotoxic effect based on pharmacological synergism, two MDR cell lines were used: Lucena (resistant to VCR) and FEPS (resistant to DNR), both derived from the K562 non-MDR cell line, by MTT analyses. The activity of Pgp was ascertained by measuring accumulation and the directional flux of Rh123. Furthermore, we performed a molecular docking simulation to delve into the molecular mechanism of PIM-1 alone, and combined with chemotherapeutic agents (VCR and DNR).Results:Our in vitro results have shown that AZD1208 alone decreases cell viability of MDR cells. However, co-exposure of AZD1208 and DNR or VCR reverses this effect. When we analyzed the ABCB1 activity AZD1208 alone was not able to affect the pump extrusion. Differently, co-exposure of AZD1208 and DNR or VCR impaired ABCB1 activity, which could be explained by compensatory expression of abcb1 or other extrusion pumps not analyzed here. Docking analysis showed that AZD1208 is capable of performing hydrophobic interactions with PIM-1 ATP- binding-site residues with stronger interaction-based negative free energy (FEB, kcal/mol) than the ATP itself, mimicking an ATP-competitive inhibitory pattern of interaction. On the same way, VCR and DNR may theoretically interact at the same biophysical environment of AZD1208 and also compete with ATP by the PIM-1 active site. These evidences suggest that AZD1208 may induce pharmacodynamic interaction with VCR and DNR, weakening its cytotoxic potential in the ATP-binding site from PIM-1 observed in the in vitro experiments.Conclusion:Finally, the current results could have a pre-clinical relevance potential in the rational polypharmacology strategies to prevent multiple-drugs resistance in human leukemia cancer therapy.

scholarly journals Identification of the ATP binding site in tyrocidine synthetase 1 by selective modification with fluorescein 5'-isothiocyanate.

1994 ◽  
Vol 269 (21) ◽  
pp. 14962-14966
Author(s):  
M. Pavela-Vrancic ◽  
E. Pfeifer ◽  
W. Schröder ◽  
H. von Döhren ◽  
H. Kleinkauf
Keyword(s):  
Binding Site ◽  
Atp Binding ◽  
Atp Binding Site

scholarly journals Crizotinib acts as ABL1 inhibitor combining ATP-binding with allosteric inhibition and is active against native BCR-ABL1 and its resistance and compound mutants BCR-ABL1T315I and BCR-ABL1T315I-E255K

2021 ◽  
Author(s):  
Afsar Ali Mian ◽  
Isabella Haberbosch ◽  
Hazem Khamaisie ◽  
Abed Agbarya ◽  
Larissa Pietsch ◽  
...  
Keyword(s):  
Binding Site ◽  
Kinase Inhibitors ◽  
Therapeutic Potential ◽  
Lymphoblastic Leukemia ◽  
Philadelphia Chromosome ◽  
Binding Pocket ◽  
Atp Binding ◽  
Atp Binding Site ◽  
Lung Cancer Patients

AbstractResistance remains the major clinical challenge for the therapy of Philadelphia chromosome–positive (Ph+) leukemia. With the exception of ponatinib, all approved tyrosine kinase inhibitors (TKIs) are unable to inhibit the common “gatekeeper” mutation T315I. Here we investigated the therapeutic potential of crizotinib, a TKI approved for targeting ALK and ROS1 in non-small cell lung cancer patients, which inhibited also the ABL1 kinase in cell-free systems, for the treatment of advanced and therapy-resistant Ph+ leukemia. By inhibiting the BCR-ABL1 kinase, crizotinib efficiently suppressed growth of Ph+ cells without affecting growth of Ph− cells. It was also active in Ph+ patient-derived long-term cultures (PD-LTCs) independently of the responsiveness/resistance to other TKIs. The efficacy of crizotinib was confirmed in vivo in syngeneic mouse models of BCR-ABL1- or BCR-ABL1T315I-driven chronic myeloid leukemia–like disease and in BCR-ABL1-driven acute lymphoblastic leukemia (ALL). Although crizotinib binds to the ATP-binding site, it also allosterically affected the myristol binding pocket, the binding site of GNF2 and asciminib (former ABL001). Therefore, crizotinib has a seemingly unique double mechanism of action, on the ATP-binding site and on the myristoylation binding pocket. These findings strongly suggest the clinical evaluation of crizotinib for the treatment of advanced and therapy-resistant Ph+ leukemia.

scholarly journals Photoaffinity labelling of the ATP-binding site of the epidermal growth factor-dependent protein kinase

1984 ◽  
Vol 220 (3) ◽  
pp. 677-683 ◽  
Author(s):  
J E Kudlow ◽  
Y Leung
Keyword(s):  
Protein Kinase ◽  
Binding Site ◽  
Egf Receptor ◽  
Light Exposure ◽  
Atp Binding ◽  
Receptor Kinase ◽  
Dependent Protein Kinase ◽  
Atp Binding Site ◽  
Dependent Protein ◽  
Epidermal Growth

Epidermal growth factor (EGF), after binding to its receptor, activates a tyrosine-specific protein kinase which phosphorylates several substrates, including the EGF receptor itself. The effects of a photoaffinity analogue of ATP, 3′-O-(3-[N-(4-azido-2-nitrophenyl)amino]propionyl)adenosine 5′-triphosphate (arylazido-beta-alanyl-ATP) on the EGF-dependent protein kinase in A431 human tumour cell plasma membrane vesicles was investigated. This analogue was capable of inactivating the EGF-receptor kinase in a photodependent manner. Partial inactivation occurred at an analogue concentration of 1 microM and complete inactivation occurred at 10 microM when a 2 min light exposure was used. Arylazido-beta-alanine at 100 microM and ATP at 100 microM were incapable of inactivating the enzyme with 2 min of light exposure. The photodependent inactivation of the enzyme by the analogue could be partially blocked by 20 mM-ATP and more effectively blocked by either 20 mM-adenosine 5′-[beta gamma-imido]triphosphate or 20 mM-guanosine 5′-[beta gamma-imido]triphosphate, indicating nucleotide-binding site specificity. Arylazido-beta-alanyl-[alpha-32P]ATP was capable of labelling membrane proteins in a photodependent manner. Numerous proteins were labelled, the most prominent of which ran with an apparent Mr of 53000 on polyacrylamide-gel electrophoresis. A band of minor intensity was seen of Mr corresponding to the EGF receptor (170000). Immunoprecipitation of affinity-labelled and solubilized membranes with an anti-(EGF receptor) monoclonal antibody demonstrated that the Mr 170000 receptor protein was photoaffinity labelled by the analogue. The Mr 53000 peptide was not specifically bound by the anti-receptor antibody. The affinity labelling of the receptor was not enhanced by EGF, suggesting that EGF stimulation of the kinase activity does not result from changes in the affinity of the kinase for ATP. These studies demonstrate that arylazido-beta-alanyl-ATP interacts with the ATP-binding site of the EGF-receptor kinase with apparent high affinity and that this analogue is an effective photoaffinity label for the kinase. Furthermore, these studies demonstrate that the EGF receptor, identified by using monoclonal antibodies, contains an ATP-binding site, providing further confirmation that the EGF receptor and EGF-dependent protein kinase are domains of the Mr 170000 protein.

scholarly journals Mutagenic Analysis of the Putative ABCC6 Substrate-Binding Cavity Using a New Homology Model

2021 ◽  
Vol 22 (13) ◽  
pp. 6910
Author(s):  
Flora Szeri ◽  
Valentina Corradi ◽  
Fatemeh Niaziorimi ◽  
Sylvia Donnelly ◽  
Gwenaëlle Conseil ◽  
...  
Keyword(s):  
Binding Site ◽  
Efflux Pump ◽  
Substrate Binding ◽  
Functional Characterization ◽  
Atp Release ◽  
Homology Model ◽  
Atp Binding ◽  
Atp Binding Site ◽  
Binding Cavity ◽  
Atp Efflux

Inactivating mutations in ABCC6 underlie the rare hereditary mineralization disorder pseudoxanthoma elasticum. ABCC6 is an ATP-binding cassette (ABC) integral membrane protein that mediates the release of ATP from hepatocytes into the bloodstream. The released ATP is extracellularly converted into pyrophosphate, a key mineralization inhibitor. Although ABCC6 is firmly linked to cellular ATP release, the molecular details of ABCC6-mediated ATP release remain elusive. Most of the currently available data support the hypothesis that ABCC6 is an ATP-dependent ATP efflux pump, an un-precedented function for an ABC transporter. This hypothesis implies the presence of an ATP-binding site in the substrate-binding cavity of ABCC6. We performed an extensive mutagenesis study using a new homology model based on recently published structures of its close homolog, bovine Abcc1, to characterize the substrate-binding cavity of ABCC6. Leukotriene C4 (LTC4), is a high-affinity substrate of ABCC1. We mutagenized fourteen amino acid residues in the rat ortholog of ABCC6, rAbcc6, that corresponded to the residues in ABCC1 found in the LTC4 binding cavity. Our functional characterization revealed that most of the amino acids in rAbcc6 corresponding to those found in the LTC4 binding pocket in bovine Abcc1 are not critical for ATP efflux. We conclude that the putative ATP binding site in the substrate-binding cavity of ABCC6/rAbcc6 is distinct from the bovine Abcc1 LTC4-binding site.

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