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Ryan P Emptage, Megan J Schoenberger, Kathryn M Ferguson, Ronen Marmorstein
Precise control of the cell cycle allows for timely repair of genetic material prior to replication. One factor intimately involved in this process is checkpoint kinase 1 (Chk1), a DNA damage repair inducing Ser/Thr protein kinase that contains an N-terminal kinase domain and a C-terminal regulatory region consisting of a ∼100-residue linker followed by a putative kinase-associated 1 (KA1) domain. We report the crystal structure of the human Chk1 KA1 domain, demonstrating striking structural homology with other sequentially diverse KA1 domains...
November 17, 2017: Journal of Biological Chemistry
Matthew R Mills, Longzhu Q Shen, David Z Zhang, Alexander D Ryabov, Terrence J Collins
Kinetic studies of the acid-induced ejection of iron(III) show that the more electron-rich tetra-amido-N macrocyclic ligand (TAML) activator [FeIII {(Me2 CNCOCMe2 NCO)2 CMe2 }OH2 ]- (4), which does not have a benzene ring in its head component ("beheaded" TAML), is up to 1 × 104 times more resistant than much less electron-rich [FeIII {1,2-C6 H4 (NCOCMe2 NCO)2 CMe2 }OH2 ]- (1a) to the electrophilic attack. This counterintuitive increased resistance is seen in both the specific acid (kobs = k1 [H+ ]/(K + [H+ ])) and phosphate general acid (kII = (kdi Ka1 + ktri [H+ ])/(Ka1 +[H+ ])) demetalation pathways...
September 5, 2017: Inorganic Chemistry
Keziban Yazici, Burcu Goksu
In this study, the effects of kaolin (M-99-099) applications on the total phenolic and antioxidant contents of tea leaves (Camellia sinensis (L.) O. Kuntze) harvested in three different periods were investigated. For this purpose, four different strategies including standard fertilizer application (T), 3% kaolin+standard fertilizer application (Ka1 ), 6% kaolin+standard fertilizer application (Ka2 ), and control (C) (nothing applied) were used to compare the effects of these strategies on total phenolic content, FRAP values, and DPPH radical scavenging capacities of tea leaves...
December 2017: Biochemical Genetics
M Vanathi, Sahil Goel, Anita Ganger, Tushar Agarwal, T Dada, Sudarshan Khokhar
PURPOSE: To study the Scheimpflug's imaging and corneal biomechanics in primary pterygium. METHODS: A prospective observational study of 55 patients with unilateral primary nasal pterygium was done. The normal fellow eyes of patients with pterygium were taken as controls. Clinical parameters noted included visual acuity, values of corneal curvature by doing Scheimpflug imaging, wavefront aberrations in terms of higher and lower-order aberrations and corneal hysteresis (CH) as well as corneal resistance factor (CRF) values by using ocular response analyzer...
April 2018: International Ophthalmology
Ryan P Emptage, Mark A Lemmon, Kathryn M Ferguson
Protein kinases are frequently regulated by intramolecular autoinhibitory interactions between protein modules that are reversed when these modules bind other 'activating' protein or membrane-bound targets. One group of kinases, the MAP/microtubule affinity-regulating kinases (MARKs) contain a poorly understood regulatory module, the KA1 (kinase associated-1) domain, at their C-terminus. KA1 domains from MARK1 and several related kinases from yeast to humans have been shown to bind membranes containing anionic phospholipids, and peptide ligands have also been reported...
February 1, 2017: Biochemical Journal
Jan Langmaier, Martin Pižl, Zdeněk Samec, Stanislav Záliš
Ion transfer voltammetry is used to estimate the acid dissociation constants Ka1 and Ka2 of the mono- and diprotonated forms of the biguanide drugs metformin (MF), phenformin (PF), and 1-phenylbiguanide (PB) in an aqueous solution. Measurements gave the pKa1 values for MFH(+), PFH(+), and PBH(+) characterizing the basicity of MF, PF, and PB, which are significantly higher than those reported in the literature. As a result, the monoprotonated forms of these biguanides should prevail in a considerably broader range of pH 1-15 (MFH(+), PFH(+)) and 2-13 (PBH(+))...
September 22, 2016: Journal of Physical Chemistry. A
Hui Ma, Jing-Xiang Wu, Jue Wang, Zhi-Xin Wang, Jia-Wei Wu
The SAD (synapses of amphids defective) kinases, including SAD-A and SAD-B, play important roles in the regulation of neuronal development, cell cycle, and energy metabolism. Our recent study of mouse SAD-A identified a unique autoinhibitory sequence (AIS), which binds at the junction of the kinase domain (KD) and the ubiquitin-associated (UBA) domain and exerts autoregulation in cooperation with UBA. Here, we report the crystal structure of the mouse SAD-B C-terminal fragment including the AIS and the kinase-associated domain 1 (KA1) at 2...
October 2016: Bioscience, Biotechnology, and Biochemistry
Gregory C Finnigan, Sarah M Sterling, Angela Duvalyan, Elizabeth N Liao, Aspram Sargsyan, Galo Garcia, Eva Nogales, Jeremy Thorner
Passage through the eukaryotic cell cycle requires processes that are tightly regulated both spatially and temporally. Surveillance mechanisms (checkpoints) exert quality control and impose order on the timing and organization of downstream events by impeding cell cycle progression until the necessary components are available and undamaged and have acted in the proper sequence. In budding yeast, a checkpoint exists that does not allow timely execution of the G2/M transition unless and until a collar of septin filaments has properly assembled at the bud neck, which is the site where subsequent cytokinesis will occur...
July 15, 2016: Molecular Biology of the Cell
Si-Min Yuan, Wen-Chao Nie, Fei He, Zhi-Wen Jia, Xiang-Dong Gao
MARK/PAR-1 protein kinases play important roles in cell polarization in animals. Kin1 and Kin2 are a pair of MARK/PAR-1 orthologs in the budding yeast Saccharomyces cerevisiae. They participate in the regulation of secretion and ER stress response. However, neither the subcellular localization of these two kinases nor whether they may have other cellular functions is clear. Here, we show that Kin2 localizes to the sites of polarized growth in addition to localization on the plasma membrane. The localization to polarity sites is mediated by two targeting domains-TD1 and TD2...
2016: PloS One
Jing-Xiang Wu, Yun-Sheng Cheng, Jue Wang, Lei Chen, Mei Ding, Jia-Wei Wu
The SAD/BRSK kinases participate in various important life processes, including neural development, cell cycle and energy metabolism. Like other members of the AMPK family, SAD contains an N-terminal kinase domain followed by the characteristic UBA and KA1 domains. Here we identify a unique autoinhibitory sequence (AIS) in SAD kinases, which exerts autoregulation in cooperation with UBA. Structural studies of mouse SAD-A revealed that UBA binds to the kinase domain in a distinct mode and, more importantly, AIS nestles specifically into the KD-UBA junction...
2015: Nature Communications
Amirarsalan Kavynifard, Gholamhossein Ebrahimipour, Alireza Ghasempour
The aim of this study was isolation and characterization of a crude oil degrader and biosurfactant-producing bacterium, along with optimization of conditions for crude oil degradation. Among 11 isolates, 5 were able to emulsify crude oil in Minimal Salt Medium (MSM) among which one isolate, named KA1, showed the highest potency for growth rate and biodegradation. The isolate was identified as Dietzia cinnamea KA1 using morphological and biochemical characteristics and 16S rRNA gene sequencing. The optimal conditions were 510 mM NaCl, pH 9...
May 2016: Journal of Basic Microbiology
Hideya Sakaguchi, Taisuke Kadoshima, Mika Soen, Nobuhiro Narii, Yoshihito Ishida, Masatoshi Ohgushi, Jun Takahashi, Mototsugu Eiraku, Yoshiki Sasai
The developing dorsomedial telencephalon includes the medial pallium, which goes on to form the hippocampus. Generating a reliable source of human hippocampal tissue is an important step for cell-based research into hippocampus-related diseases. Here we show the generation of functional hippocampal granule- and pyramidal-like neurons from self-organizing dorsomedial telencephalic tissue using human embryonic stem cells (hESCs). First, we develop a hESC culture method that utilizes bone morphogenetic protein (BMP) and Wnt signalling to induce choroid plexus, the most dorsomedial portion of the telencephalon...
2015: Nature Communications
Minggen Cheng, Kai Chen, Suhui Guo, Xing Huang, Jian He, Shunpeng Li, Jiandong Jiang
The 3-phenoxybenzoate (3-PBA) 1',2'-dioxygenase gene cluster (pbaA1A2B cluster), which is responsible for catalyzing 3-phenoxybenzoate to 3-hydroxybenzoate and catechol, is inducibly expressed in Sphingobium wenxiniae strain JZ-1(T) by its substrate 3-PBA. In this study, we identified a transcriptional activator of the pbaA1A2B cluster, PbaR, using a DNA affinity approach. PbaR is a 253-amino-acid protein with a molecular mass of 28,000 Da. PbaR belongs to the IclR family of transcriptional regulators and shows 99% identity to a putative transcriptional regulator that is located on the carbazole-degrading plasmid pCAR3 in Sphingomonas sp...
December 2015: Applied and Environmental Microbiology
Nidal Al-Huniti, Sunny Chapel, Hongmei Xu, Khanh H Bui, Mark Sostek
AIMS: Naloxegol, a polyethylene glycol conjugated derivative of the opioid antagonist naloxone, is in clinical development for treatment of opioid-induced constipation (OIC). The aim of the study was to develop a population pharmacokinetic model describing the concentration vs. time profile of orally administered naloxegol, and determine the impact of pre-specified demographic and clinical factors and concomitant medication on population estimates of apparent clearance (CL/F) and apparent central compartment volume of distribution (Vc /F)...
January 2016: British Journal of Clinical Pharmacology
Veronique A J Smits, David A Gillespie
Checkpoint kinase 1 (Chk1) is a master regulator of the DNA damage and replication checkpoints in vertebrate cells. When activated via phosphorylation by its upstream regulatory kinase, ATR, Chk1 prevents cells with damaged or incompletely replicated DNA from entering mitosis, and acts to stabilize stalled replication forks and suppress replication origin firing when DNA synthesis is inhibited. Chk1 blocks mitosis by maintaining high levels of inhibitory tyrosine phosphorylation of the mitotic cyclin-dependent kinase 1; however, the mechanisms that underlie replication fork stabilization and suppression of origin firing are less well defined...
October 2015: FEBS Journal
Benjamin John Floyd Dean, Sarah J B Snelling, Stephanie G Dakin, Richard J Murphy, Muhammad Kassim Javaid, Andrew Jonathan Carr
INTRODUCTION: The relationship between peripheral tissue characteristics and pain symptoms in soft tissue inflammation is poorly understood. The primary aim of this study was to determine immunohistochemical differences in tissue obtained from patients with persistent pain and patients who had become pain-free after surgical treatment for rotator cuff tendinopathy. The secondary aim was to investigate whether there would be differences in glutaminergic and inflammatory gene expression between disease-derived and healthy control cells in vitro...
July 10, 2015: Arthritis Research & Therapy
Valeria Lanza, Roberta D'Agata, Giuseppe Iacono, Francesco Bellia, Giuseppe Spoto, Graziella Vecchio
Transition metal ion complexes of a number of chelators have been widely investigated due to their biological properties. The sugar conjugation of metal complexes has resulted in improved properties of the systems, such as solubility and lectin recognition. In this paper, we report the synthesis, the characterization of new glucose and galactose conjugates of 1,4,8,11-tetraazacyclotetradecane (cyclam) and their Cu(II) complexes. The glycoconjugates were proved to be protective agents of metal-induced amyloid aggregation...
December 2015: Journal of Inorganic Biochemistry
Eun-Yeung Gong, Veronique A J Smits, Felipe Fumagallo, Desiree Piscitello, Nick Morrice, Raimundo Freire, David A Gillespie
The Chk1 protein kinase is activated in response to DNA damage through ATR-mediated phosphorylation at multiple serine-glutamine (SQ) residues within the C-terminal regulatory domain, however the molecular mechanism is not understood. Modelling indicates a high probability that this region of Chk1 contains a kinase-associated 1 (KA1) domain, a small, compact protein fold found in multiple protein kinases including SOS2, AMPK and MARK3. We introduced mutations into Chk1 designed to disrupt specific structural elements of the predicted KA1 domain...
June 3, 2015: Scientific Reports
Wang Jiannong, Jiang Junjie, Xie Yanming, Wei Xu, Li Jianpeng, Duan Jingli, Xiong Xin
OBJECTIVE: To characterize naringenin (NAR) pop- ulation pharmacokinetics (PPK) in Chinese women with primary osteoporosis. METHODS: Ninety-eight female patients with primary osteoporosis from the Jingshan, Beixinqiao, Jiaodaokou, Chaoyangmen, and Donghuamen communities in Beijing, China, aged 40 to 80 years, re- ceived oral Qianggu capsules (250 mg). Blood samples were collected before and at 0.5, 1, 2, 3, 4, 6, 8, 10, 12, and 24 h after administration. The concentration of NAR in the blood samples was measured using high performance liquid chromatography-tandem mass spectrometry...
April 2015: Journal of Traditional Chinese Medicine, Chung i Tsa Chih Ying Wen Pan
Raluca Pop, Maria Ilici, Mihaiela Andoni, Vasile N Bercean, Cornelia Muntean, Monica M Venter, Ilie Julean
The acidity constants Ka1 and Ka2 of 2-(5-mercapto-1,3,4-thiadiazol-2-ylthio)acetic acid have been determined both by experimental and theoretical methods. pKa computations at B3LYP/6-311+G(d,p) level of theory were carried out for the two tautomeric forms, thiol and thione, of the above-mentioned acid. Comparisons between the experimental and theoretical values led to the establishing of the most stable tautomer of 2-(5-mercapto-1,3,4-thiadiazol-2-ylthio)acetic acid in aqueous solution. Also, a DFT study regarding the reactivity, aromaticity and population analysis of the two tautomers has been performed...
2015: Acta Chimica Slovenica
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