Natural flavonoid morin showed anti-bacterial activity against Vibrio cholera after binding with cell division protein FtsA near ATP binding site

Author(s):  
Debasish Nag ◽  
Debabrata Ghosh Dastidar ◽  
Gopal Chakrabarti
2009 ◽  
Vol 191 (12) ◽  
pp. 3772-3784 ◽  
Author(s):  
S. J. Ryan Arends ◽  
Ryan J. Kustusch ◽  
David S. Weiss

ABSTRACT FtsE and FtsX of Escherichia coli constitute an apparent ABC transporter that localizes to the septal ring. In the absence of FtsEX, cells divide poorly and several membrane proteins essential for cell division are largely absent from the septal ring, including FtsK, FtsQ, FtsI, and FtsN. These observations, together with the fact that ftsE and ftsX are cotranscribed with ftsY, which helps to target some proteins for insertion into the cytoplasmic membrane, suggested that FtsEX might contribute to insertion of division proteins into the membrane. Here we show that this hypothesis is probably wrong, because cells depleted of FtsEX had normal amounts of FtsK, FtsQ, FtsI, and FtsN in the membrane fraction. We also show that FtsX localizes to septal rings in cells that lack FtsE, arguing that FtsX targets the FtsEX complex to the ring. Nevertheless, both proteins had to be present to recruit further Fts proteins to the ring. Mutant FtsE proteins with lesions in the ATP-binding site supported septal ring assembly (when produced together with FtsX), but these rings constricted poorly. This finding implies that FtsEX uses ATP to facilitate constriction rather than assembly of the septal ring. Finally, topology analysis revealed that FtsX has only four transmembrane segments, none of which contains a charged amino acid. This structure is not what one would expect of a substrate-specific transmembrane channel, leading us to suggest that FtsEX is not really a transporter even though it probably has to hydrolyze ATP to support cell division.


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 ◽  
...  

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.


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

Author(s):  
Afsar Ali Mian ◽  
Isabella Haberbosch ◽  
Hazem Khamaisie ◽  
Abed Agbarya ◽  
Larissa Pietsch ◽  
...  

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.


1984 ◽  
Vol 220 (3) ◽  
pp. 677-683 ◽  
Author(s):  
J E Kudlow ◽  
Y Leung

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.


2021 ◽  
Vol 22 (13) ◽  
pp. 6910
Author(s):  
Flora Szeri ◽  
Valentina Corradi ◽  
Fatemeh Niaziorimi ◽  
Sylvia Donnelly ◽  
Gwenaëlle Conseil ◽  
...  

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.


2007 ◽  
Vol 47 (supplement) ◽  
pp. S33
Author(s):  
Kazunobu Takahashi ◽  
Kosuke Maki ◽  
Kunihiro Kuwajima

Sign in / Sign up

Export Citation Format

Share Document