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Specificity and affinity of the N-terminal residues in staphylocoagulase in binding to prothrombin.
Maddur AA, Kroh HK, Aschenbrenner ME, Gibson BHY, Panizzi P, Sheehan JH, Meiler J, Bock PE, Verhamme IM
(2020) J Biol Chem 295: 5614-5625
MeSH Terms: Bacterial Proteins, Binding Sites, Coagulase, Humans, Models, Molecular, Protein Binding, Prothrombin, Staphylococcal Infections, Staphylococcus aureus, Substrate Specificity
Show Abstract · Added March 21, 2020
In -caused endocarditis, the pathogen secretes staphylocoagulase (SC), thereby activating human prothrombin (ProT) and evading immune clearance. A previous structural comparison of the SC(1-325) fragment bound to thrombin and its inactive precursor prethrombin 2 has indicated that SC activates ProT by inserting its N-terminal dipeptide Ile-Val into the ProT Ile pocket, forming a salt bridge with ProT's Asp, thereby stabilizing the active conformation. We hypothesized that these N-terminal SC residues modulate ProT binding and activation. Here, we generated labeled SC(1-246) as a probe for competitively defining the affinities of N-terminal SC(1-246) variants preselected by modeling. Using ProT(R155Q,R271Q,R284Q) (ProT), a variant refractory to prothrombinase- or thrombin-mediated cleavage, we observed variant affinities between ∼1 and 650 nm and activation potencies ranging from 1.8-fold that of WT SC(1-246) to complete loss of function. Substrate binding to ProT caused allosteric tightening of the affinity of most SC(1-246) variants, consistent with zymogen activation through occupation of the specificity pocket. Conservative changes at positions 1 and 2 were well-tolerated, with Val-Val, Ile-Ala, and Leu-Val variants exhibiting ProT affinity and activation potency comparable with WT SC(1-246). Weaker binding variants typically had reduced activation rates, although at near-saturating ProT levels, several variants exhibited limiting rates similar to or higher than that of WT SC(1-246). The Ile pocket in ProT appears to favor nonpolar, nonaromatic residues at SC positions 1 and 2. Our results suggest that SC variants other than WT Ile-Val-Thr might emerge with similar ProT-activating efficiency.
© 2020 Maddur et al.
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10 MeSH Terms
Engineering cytochrome P450 enzyme systems for biomedical and biotechnological applications.
Li Z, Jiang Y, Guengerich FP, Ma L, Li S, Zhang W
(2020) J Biol Chem 295: 833-849
MeSH Terms: Biocatalysis, Biotechnology, Cytochrome P-450 Enzyme System, Metabolic Engineering, Protein Engineering, Steroids, Substrate Specificity, Xenobiotics
Show Abstract · Added March 3, 2020
Cytochrome P450 enzymes (P450s) are broadly distributed among living organisms and play crucial roles in natural product biosynthesis, degradation of xenobiotics, steroid biosynthesis, and drug metabolism. P450s are considered as the most versatile biocatalysts in nature because of the vast variety of substrate structures and the types of reactions they catalyze. In particular, P450s can catalyze regio- and stereoselective oxidations of nonactivated C-H bonds in complex organic molecules under mild conditions, making P450s useful biocatalysts in the production of commodity pharmaceuticals, fine or bulk chemicals, bioremediation agents, flavors, and fragrances. Major efforts have been made in engineering improved P450 systems that overcome the inherent limitations of the native enzymes. In this review, we focus on recent progress of different strategies, including protein engineering, redox-partner engineering, substrate engineering, electron source engineering, and P450-mediated metabolic engineering, in efforts to more efficiently produce pharmaceuticals and other chemicals. We also discuss future opportunities for engineering and applications of the P450 systems.
© 2020 Li et al.
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8 MeSH Terms
Human cytochrome P450 enzymes bind drugs and other substrates mainly through conformational-selection modes.
Guengerich FP, Wilkey CJ, Phan TTN
(2019) J Biol Chem 294: 10928-10941
MeSH Terms: Catalysis, Cytochrome P-450 CYP2D6, Cytochrome P-450 CYP2E1, Cytochrome P-450 CYP3A, Cytochrome P-450 Enzyme Inhibitors, Cytochrome P-450 Enzyme System, Humans, Kinetics, Lauric Acids, Ligands, Molecular Conformation, Oxidation-Reduction, Palmitic Acid, Protein Binding, Protein Conformation, Spiro Compounds, Substrate Specificity
Show Abstract · Added March 3, 2020
Cytochrome P450 (P450) enzymes are major catalysts involved in the oxidations of most drugs, steroids, carcinogens, fat-soluble vitamins, and natural products. The binding of substrates to some of the 57 human P450s and other mammalian P450s is more complex than a two-state system and has been proposed to involve mechanisms such as multiple ligand occupancy, induced-fit, and conformational-selection. Here, we used kinetic analysis of binding with multiple concentrations of substrates and computational modeling of these data to discern possible binding modes of several human P450s. We observed that P450 2D6 binds its ligand rolapitant in a mechanism involving conformational-selection. P450 4A11 bound the substrate lauric acid via conformational-selection, as did P450 2C8 with palmitic acid. Binding of the steroid progesterone to P450 21A2 was also best described by a conformational-selection model. Hexyl isonicotinate binding to P450 2E1 could be described by either a conformational-selection or an induced-fit model. Simulation of the binding of the ligands midazolam, bromocriptine, testosterone, and ketoconazole to P450 3A4 was consistent with an induced-fit or a conformational-selection model, but the concentration dependence of binding rates for varying both P450 3A4 and midazolam concentrations revealed discordance in the parameters, indicative of conformational-selection. Binding of the P450s 2C8, 2D6, 3A4, 4A11, and 21A2 was best described by conformational-selection, and P450 2E1 appeared to fit either mode. These findings highlight the complexity of human P450-substrate interactions and that conformational-selection is a dominant feature of many of these interactions.
© 2019 Guengerich et al.
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17 MeSH Terms
Conformational selection dominates binding of steroids to human cytochrome P450 17A1.
Guengerich FP, Wilkey CJ, Glass SM, Reddish MJ
(2019) J Biol Chem 294: 10028-10041
MeSH Terms: 17-alpha-Hydroxypregnenolone, 17-alpha-Hydroxyprogesterone, Androstenes, Humans, Kinetics, Protein Conformation, Steroid 17-alpha-Hydroxylase, Substrate Specificity
Show Abstract · Added March 3, 2020
Cytochrome P450 (P450, CYP) enzymes are the major catalysts involved in the oxidation of steroids as well as many other compounds. Their versatility has been explained in part by flexibility of the proteins and complexity of the binding mechanisms. However, whether these proteins bind their substrates via induced fit or conformational selection is not understood. P450 17A1 has a major role in steroidogenesis, catalyzing the two-step oxidations of progesterone and pregnenolone to androstenedione and dehydroepiandrosterone, respectively, via 17α-hydroxy (OH) intermediates. We examined the interaction of P450 17A1 with its steroid substrates by analyzing progress curves (UV-visible spectroscopy), revealing that the rates of binding of any of these substrates decreased with increasing substrate concentration, a hallmark of conformational selection. Further, when the concentration of 17α-OH pregnenolone was held constant and the P450 concentration increased, the binding rate increased, and such opposite patterns are also diagnostic of conformational selection. Kinetic simulation modeling was also more consistent with conformational selection than with an induced-fit mechanism. Cytochrome partially enhances P450 17A1 lyase activity by altering the P450 17A1 conformation but did not measurably alter the binding of 17α-OH pregnenolone or 17α-OH progesterone, as judged by the apparent and binding kinetics. The P450 17A1 inhibitor abiraterone also bound to P450 17A1 in a multistep manner, and modeling indicated that the selective inhibition of the two P450 17A1 steps by the drug orteronel can be rationalized only by a multiple-conformation model. In conclusion, P450 17A1 binds its steroid substrates via conformational selection.
© 2019 Guengerich et al.
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MeSH Terms
A Novel Class of Common Docking Domain Inhibitors That Prevent ERK2 Activation and Substrate Phosphorylation.
Sammons RM, Perry NA, Li Y, Cho EJ, Piserchio A, Zamora-Olivares DP, Ghose R, Kaoud TS, Debevec G, Bartholomeusz C, Gurevich VV, Iverson TM, Giulianotti M, Houghten RA, Dalby KN
(2019) ACS Chem Biol 14: 1183-1194
MeSH Terms: Binding Sites, Crystallography, X-Ray, Dose-Response Relationship, Drug, Enzyme Activation, Guanidine, Humans, Mitogen-Activated Protein Kinase 1, Nuclear Magnetic Resonance, Biomolecular, Phosphorylation, Protein Kinase Inhibitors, Substrate Specificity
Show Abstract · Added March 18, 2020
Extracellular signal-regulated kinases (ERK1/2) are mitogen-activated protein kinases (MAPKs) that play a pro-tumorigenic role in numerous cancers. ERK1/2 possess two protein-docking sites that are distinct from the active site: the D-recruitment site (DRS) and the F-recruitment site. These docking sites facilitate substrate recognition, intracellular localization, signaling specificity, and protein complex assembly. Targeting these sites on ERK in a therapeutic context may overcome many problems associated with traditional ATP-competitive inhibitors. Here, we identified a new class of inhibitors that target the ERK DRS by screening a synthetic combinatorial library of more than 30 million compounds. The screen detects the competitive displacement of a fluorescent peptide from the DRS of ERK2. The top molecular scaffold from the screen was optimized for structure-activity relationship by positional scanning of different functional groups. This resulted in 10 compounds with similar binding affinities and a shared core structure consisting of a tertiary amine hub with three functionalized cyclic guanidino branches. Compound 2507-1 inhibited ERK2 from phosphorylating a DRS-targeting substrate and prevented the phosphorylation of ERK2 by a constitutively active MEK1 (MAPK/ERK kinase 1) mutant. Interaction between an analogue, 2507-8, and the ERK2 DRS was confirmed by nuclear magnetic resonance and X-ray crystallography. 2507-8 forms critical interactions at the common docking domain residue Asp319 via an arginine-like moiety that is shared by all 10 hits, suggesting a common binding mode. The structural and biochemical insights reported here provide the basis for developing new ERK inhibitors that are not ATP-competitive but instead function by disrupting critical protein-protein interactions.
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Axonal organization defects in the hippocampus of adult conditional BACE1 knockout mice.
Ou-Yang MH, Kurz JE, Nomura T, Popovic J, Rajapaksha TW, Dong H, Contractor A, Chetkovich DM, Tourtellotte WG, Vassar R
(2018) Sci Transl Med 10:
MeSH Terms: Aging, Amyloid Precursor Protein Secretases, Animals, Animals, Newborn, Apoptosis, Aspartic Acid Endopeptidases, Axons, Cognition, Epilepsy, Gene Deletion, Hippocampus, Long-Term Potentiation, Memory Disorders, Mice, Inbred C57BL, Mice, Knockout, Myelin Sheath, Neurogenesis, Phenotype, Substrate Specificity
Show Abstract · Added April 2, 2019
β-Site APP (amyloid precursor protein) cleaving enzyme 1 (BACE1) is the β-secretase enzyme that initiates production of the toxic amyloid-β peptide that accumulates in the brains of patients with Alzheimer's disease (AD). Hence, BACE1 is a prime therapeutic target, and several BACE1 inhibitor drugs are currently being tested in clinical trials for AD. However, the safety of BACE1 inhibition is unclear. Germline BACE1 knockout mice have multiple neurological phenotypes, although these could arise from BACE1 deficiency during development. To address this question, we report that tamoxifen-inducible conditional BACE1 knockout mice in which the gene was ablated in the adult largely lacked the phenotypes observed in germline BACE1 knockout mice. However, one BACE1-null phenotype was induced after gene deletion in the adult mouse brain. This phenotype showed reduced length and disorganization of the hippocampal mossy fiber infrapyramidal bundle, the axonal pathway of dentate gyrus granule cells that is maintained by neurogenesis in the mouse brain. This defect in axonal organization correlated with reduced BACE1-mediated cleavage of the neural cell adhesion protein close homolog of L1 (CHL1), which has previously been associated with axon guidance. Although our results indicate that BACE1 inhibition in the adult mouse brain may avoid phenotypes associated with BACE1 deficiency during embryonic and postnatal development, they also suggest that BACE1 inhibitor drugs developed for treating AD may disrupt the organization of an axonal pathway in the hippocampus, an important structure for learning and memory.
Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
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19 MeSH Terms
VHL substrate transcription factor ZHX2 as an oncogenic driver in clear cell renal cell carcinoma.
Zhang J, Wu T, Simon J, Takada M, Saito R, Fan C, Liu XD, Jonasch E, Xie L, Chen X, Yao X, Teh BT, Tan P, Zheng X, Li M, Lawrence C, Fan J, Geng J, Liu X, Hu L, Wang J, Liao C, Hong K, Zurlo G, Parker JS, Auman JT, Perou CM, Rathmell WK, Kim WY, Kirschner MW, Kaelin WG, Baldwin AS, Zhang Q
(2018) Science 361: 290-295
MeSH Terms: Animals, Carcinoma, Renal Cell, Chromatin Immunoprecipitation, Female, Gene Expression Regulation, Neoplastic, Homeodomain Proteins, Humans, Hydroxylation, Kidney Neoplasms, Mice, Mice, SCID, Molecular Targeted Therapy, Mutation, NF-kappa B, Oncogenes, Substrate Specificity, Transcription Factors, Von Hippel-Lindau Tumor Suppressor Protein
Show Abstract · Added October 30, 2019
Inactivation of the von Hippel-Lindau (VHL) E3 ubiquitin ligase protein is a hallmark of clear cell renal cell carcinoma (ccRCC). Identifying how pathways affected by VHL loss contribute to ccRCC remains challenging. We used a genome-wide in vitro expression strategy to identify proteins that bind VHL when hydroxylated. Zinc fingers and homeoboxes 2 (ZHX2) was found as a VHL target, and its hydroxylation allowed VHL to regulate its protein stability. Tumor cells from ccRCC patients with loss-of-function mutations usually had increased abundance and nuclear localization of ZHX2. Functionally, depletion of ZHX2 inhibited VHL-deficient ccRCC cell growth in vitro and in vivo. Mechanistically, integrated chromatin immunoprecipitation sequencing and microarray analysis showed that ZHX2 promoted nuclear factor κB activation. These studies reveal ZHX2 as a potential therapeutic target for ccRCC.
Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
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Discovery, Characterization, and Effects on Renal Fluid and Electrolyte Excretion of the Kir4.1 Potassium Channel Pore Blocker, VU0134992.
Kharade SV, Kurata H, Bender AM, Blobaum AL, Figueroa EE, Duran A, Kramer M, Days E, Vinson P, Flores D, Satlin LM, Meiler J, Weaver CD, Lindsley CW, Hopkins CR, Denton JS
(2018) Mol Pharmacol 94: 926-937
MeSH Terms: Animals, Binding Sites, Diuretics, Electrolytes, HEK293 Cells, Humans, Male, Models, Molecular, Molecular Docking Simulation, Molecular Structure, Mutagenesis, Site-Directed, Potassium Channels, Inwardly Rectifying, Rats, Small Molecule Libraries, Substrate Specificity
Show Abstract · Added April 10, 2019
The inward rectifier potassium (Kir) channel Kir4.1 () carries out important physiologic roles in epithelial cells of the kidney, astrocytes in the central nervous system, and stria vascularis of the inner ear. Loss-of-function mutations in lead to EAST/SeSAME syndrome, which is characterized by epilepsy, ataxia, renal salt wasting, and sensorineural deafness. Although genetic approaches have been indispensable for establishing the importance of Kir4.1 in the normal function of these tissues, the availability of pharmacological tools for acutely manipulating the activity of Kir4.1 in genetically normal animals has been lacking. We therefore carried out a high-throughput screen of 76,575 compounds from the Vanderbilt Institute of Chemical Biology library for small-molecule modulators of Kir4.1. The most potent inhibitor identified was 2-(2-bromo-4-isopropylphenoxy)--(2,2,6,6-tetramethylpiperidin-4-yl)acetamide (VU0134992). In whole-cell patch-clamp electrophysiology experiments, VU0134992 inhibits Kir4.1 with an IC value of 0.97 M and is 9-fold selective for homomeric Kir4.1 over Kir4.1/5.1 concatemeric channels (IC = 9 M) at -120 mV. In thallium (Tl) flux assays, VU0134992 is greater than 30-fold selective for Kir4.1 over Kir1.1, Kir2.1, and Kir2.2; is weakly active toward Kir2.3, Kir6.2/SUR1, and Kir7.1; and is equally active toward Kir3.1/3.2, Kir3.1/3.4, and Kir4.2. This potency and selectivity profile is superior to Kir4.1 inhibitors amitriptyline, nortriptyline, and fluoxetine. Medicinal chemistry identified components of VU0134992 that are critical for inhibiting Kir4.1. Patch-clamp electrophysiology, molecular modeling, and site-directed mutagenesis identified pore-lining glutamate 158 and isoleucine 159 as critical residues for block of the channel. VU0134992 displayed a large free unbound fraction () in rat plasma ( = 0.213). Consistent with the known role of Kir4.1 in renal function, oral dosing of VU0134992 led to a dose-dependent diuresis, natriuresis, and kaliuresis in rats. Thus, VU0134992 represents the first in vivo active tool compound for probing the therapeutic potential of Kir4.1 as a novel diuretic target for the treatment of hypertension.
Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.
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Structural basis of ligand binding modes at the neuropeptide Y Y receptor.
Yang Z, Han S, Keller M, Kaiser A, Bender BJ, Bosse M, Burkert K, Kögler LM, Wifling D, Bernhardt G, Plank N, Littmann T, Schmidt P, Yi C, Li B, Ye S, Zhang R, Xu B, Larhammar D, Stevens RC, Huster D, Meiler J, Zhao Q, Beck-Sickinger AG, Buschauer A, Wu B
(2018) Nature 556: 520-524
MeSH Terms: Arginine, Binding Sites, Crystallography, X-Ray, Dihydropyridines, Diphenylacetic Acids, Humans, Inositol Phosphates, Ligands, Molecular Docking Simulation, Mutant Proteins, Mutation, Neuropeptide Y, Nuclear Magnetic Resonance, Biomolecular, Phenylurea Compounds, Protein Binding, Receptors, Neuropeptide Y, Structure-Activity Relationship, Substrate Specificity
Show Abstract · Added March 21, 2020
Neuropeptide Y (NPY) receptors belong to the G-protein-coupled receptor superfamily and have important roles in food intake, anxiety and cancer biology . The NPY-Y receptor system has emerged as one of the most complex networks with three peptide ligands (NPY, peptide YY and pancreatic polypeptide) binding to four receptors in most mammals, namely the Y, Y, Y and Y receptors, with different affinity and selectivity . NPY is the most powerful stimulant of food intake and this effect is primarily mediated by the Y receptor (YR) . A number of peptides and small-molecule compounds have been characterized as YR antagonists and have shown clinical potential in the treatment of obesity , tumour and bone loss . However, their clinical usage has been hampered by low potency and selectivity, poor brain penetration ability or lack of oral bioavailability . Here we report crystal structures of the human YR bound to the two selective antagonists UR-MK299 and BMS-193885 at 2.7 and 3.0 Å resolution, respectively. The structures combined with mutagenesis studies reveal the binding modes of YR to several structurally diverse antagonists and the determinants of ligand selectivity. The YR structure and molecular docking of the endogenous agonist NPY, together with nuclear magnetic resonance, photo-crosslinking and functional studies, provide insights into the binding behaviour of the agonist and for the first time, to our knowledge, determine the interaction of its N terminus with the receptor. These insights into YR can enable structure-based drug discovery that targets NPY receptors.
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Identifying the substrate proteins of U-box E3s E4B and CHIP by orthogonal ubiquitin transfer.
Bhuripanyo K, Wang Y, Liu X, Zhou L, Liu R, Duong D, Zhao B, Bi Y, Zhou H, Chen G, Seyfried NT, Chazin WJ, Kiyokawa H, Yin J
(2018) Sci Adv 4: e1701393
MeSH Terms: Amino Acid Sequence, Bacteriophages, Biocatalysis, Cyclin-Dependent Kinase 4, Endoplasmic Reticulum Stress, HEK293 Cells, Humans, Mutant Proteins, Mutation, Peptides, Proteolysis, Reproducibility of Results, Signal Transduction, Substrate Specificity, Tumor Suppressor Protein p53, Tumor Suppressor Proteins, Ubiquitin, Ubiquitin-Protein Ligase Complexes, Ubiquitin-Protein Ligases, Ubiquitination
Show Abstract · Added March 24, 2018
E3 ubiquitin (UB) ligases E4B and carboxyl terminus of Hsc70-interacting protein (CHIP) use a common U-box motif to transfer UB from E1 and E2 enzymes to their substrate proteins and regulate diverse cellular processes. To profile their ubiquitination targets in the cell, we used phage display to engineer E2-E4B and E2-CHIP pairs that were free of cross-reactivity with the native UB transfer cascades. We then used the engineered E2-E3 pairs to construct "orthogonal UB transfer (OUT)" cascades so that a mutant UB (xUB) could be exclusively used by the engineered E4B or CHIP to label their substrate proteins. Purification of xUB-conjugated proteins followed by proteomics analysis enabled the identification of hundreds of potential substrates of E4B and CHIP in human embryonic kidney 293 cells. Kinase MAPK3 (mitogen-activated protein kinase 3), methyltransferase PRMT1 (protein arginine -methyltransferase 1), and phosphatase PPP3CA (protein phosphatase 3 catalytic subunit alpha) were identified as the shared substrates of the two E3s. Phosphatase PGAM5 (phosphoglycerate mutase 5) and deubiquitinase OTUB1 (ovarian tumor domain containing ubiquitin aldehyde binding protein 1) were confirmed as E4B substrates, and β-catenin and CDK4 (cyclin-dependent kinase 4) were confirmed as CHIP substrates. On the basis of the CHIP-CDK4 circuit identified by OUT, we revealed that CHIP signals CDK4 degradation in response to endoplasmic reticulum stress.
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20 MeSH Terms