Chen CK

References (4)

Title : Anti-Acetylcholinesterase Alkaloids from Annona glabra Leaf - Lee_2015_Nat.Prod.Commun_10_891
Author(s) : Lee SS , Wu DY , Tsai SF , Chen CK
Ref : Nat Prod Commun , 10 :891 , 2015
Abstract : Bioassay guided fractionation and separation of the EtOH extract of Annona glabra leaf against acetylcholinesterse led to the characterization of 15 alkaloids. Among them, (-)-actinodaphnine (2) and (-)-(6aS,7R)-7-hydroxyactinodaphnine (9) are new aporphines, although (+)-2 and (+/-)-2 have been found in several plants. Their structures were established by spectroscopic analysis. (-)-Anolobine (5) and (-)-roemeroline (8) showed moderate inhibitory activity against eel acetylcholinesterase with IC50 values of 22.4 and 26.3 muM, respectively.
ESTHER : Lee_2015_Nat.Prod.Commun_10_891
PubMedSearch : Lee_2015_Nat.Prod.Commun_10_891
PubMedID: 26197510

Title : Structure of the alkalohyperthermophilic Archaeoglobus fulgidus lipase contains a unique C-terminal domain essential for long-chain substrate binding - Chen_2009_J.Mol.Biol_390_672
Author(s) : Chen CK , Lee GC , Ko TP , Guo RT , Huang LM , Liu HJ , Ho YF , Shaw JF , Wang AH
Ref : Journal of Molecular Biology , 390 :672 , 2009
Abstract : Several crystal structures of AFL, a novel lipase from the archaeon Archaeoglobus fulgidus, complexed with various ligands, have been determined at about 1.8 A resolution. This enzyme has optimal activity in the temperature range of 70-90 degrees C and pH 10-11. AFL consists of an N-terminal alpha/beta-hydrolase fold domain, a small lid domain, and a C-terminal beta-barrel domain. The N-terminal catalytic domain consists of a 6-stranded beta-sheet flanked by seven alpha-helices, four on one side and three on the other side. The C-terminal lipid binding domain consists of a beta-sheet of 14 strands and a substrate covering motif on top of the highly hydrophobic substrate binding site. The catalytic triad residues (Ser136, Asp163, and His210) and the residues forming the oxyanion hole (Leu31 and Met137) are in positions similar to those of other lipases. Long-chain lipid is located across the two domains in the AFL-substrate complex. Structural comparison of the catalytic domain of AFL with a homologous lipase from Bacillus subtilis reveals an opposite substrate binding orientation in the two enzymes. AFL has a higher preference toward long-chain substrates whose binding site is provided by a hydrophobic tunnel in the C-terminal domain. The unusually large interacting surface area between the two domains may contribute to thermostability of the enzyme. Two amino acids, Asp61 and Lys101, are identified as hinge residues regulating movement of the lid domain. The hydrogen-bonding pattern associated with these two residues is pH dependent, which may account for the optimal enzyme activity at high pH. Further engineering of this novel lipase with high temperature and alkaline stability will find its use in industrial applications.
ESTHER : Chen_2009_J.Mol.Biol_390_672
PubMedSearch : Chen_2009_J.Mol.Biol_390_672
PubMedID: 19447113
Gene_locus related to this paper: arcfu-AF1763

Title : DNA sequence of human chromosome 17 and analysis of rearrangement in the human lineage - Zody_2006_Nature_440_1045
Author(s) : Zody MC , Garber M , Adams DJ , Sharpe T , Harrow J , Lupski JR , Nicholson C , Searle SM , Wilming L , Young SK , Abouelleil A , Allen NR , Bi W , Bloom T , Borowsky ML , Bugalter BE , Butler J , Chang JL , Chen CK , Cook A , Corum B , Cuomo CA , de Jong PJ , Decaprio D , Dewar K , FitzGerald M , Gilbert J , Gibson R , Gnerre S , Goldstein S , Grafham DV , Grocock R , Hafez N , Hagopian DS , Hart E , Norman CH , Humphray S , Jaffe DB , Jones M , Kamal M , Khodiyar VK , LaButti K , Laird G , Lehoczky J , Liu X , Lokyitsang T , Loveland J , Lui A , Macdonald P , Major JE , Matthews L , Mauceli E , McCarroll SA , Mihalev AH , Mudge J , Nguyen C , Nicol R , O'Leary SB , Osoegawa K , Schwartz DC , Shaw-Smith C , Stankiewicz P , Steward C , Swarbreck D , Venkataraman V , Whittaker CA , Yang X , Zimmer AR , Bradley A , Hubbard T , Birren BW , Rogers J , Lander ES , Nusbaum C
Ref : Nature , 440 :1045 , 2006
Abstract : Chromosome 17 is unusual among the human chromosomes in many respects. It is the largest human autosome with orthology to only a single mouse chromosome, mapping entirely to the distal half of mouse chromosome 11. Chromosome 17 is rich in protein-coding genes, having the second highest gene density in the genome. It is also enriched in segmental duplications, ranking third in density among the autosomes. Here we report a finished sequence for human chromosome 17, as well as a structural comparison with the finished sequence for mouse chromosome 11, the first finished mouse chromosome. Comparison of the orthologous regions reveals striking differences. In contrast to the typical pattern seen in mammalian evolution, the human sequence has undergone extensive intrachromosomal rearrangement, whereas the mouse sequence has been remarkably stable. Moreover, although the human sequence has a high density of segmental duplication, the mouse sequence has a very low density. Notably, these segmental duplications correspond closely to the sites of structural rearrangement, demonstrating a link between duplication and rearrangement. Examination of the main classes of duplicated segments provides insight into the dynamics underlying expansion of chromosome-specific, low-copy repeats in the human genome.
ESTHER : Zody_2006_Nature_440_1045
PubMedSearch : Zody_2006_Nature_440_1045
PubMedID: 16625196
Gene_locus related to this paper: human-NLGN2 , human-NOTUM

Title : Co-expression of Gbeta5 enhances the function of two Ggamma subunit-like domain-containing regulators of G protein signaling proteins - Kovoor_2000_J.Biol.Chem_275_3397
Author(s) : Kovoor A , Chen CK , He W , Wensel TG , Simon MI , Lester HA
Ref : Journal of Biological Chemistry , 275 :3397 , 2000
Abstract : Regulators of G protein signaling (RGS) stimulate the GTPase activity of G protein Galpha subunits and probably play additional roles. Some RGS proteins contain a Ggamma subunit-like (GGL) domain, which mediates a specific interaction with Gbeta5. The role of such interactions in RGS function is unclear. RGS proteins can accelerate the kinetics of coupling of G protein-coupled receptors to G-protein-gated inwardly rectifying K(+) (GIRK) channels. Therefore, we coupled m2-muscarinic acetylcholine receptors to GIRK channels in Xenopus oocytes to evaluate the effect of Gbeta5 on RGS function. Co-expression of either RGS7 or RGS9 modestly accelerated GIRK channel kinetics. When Gbeta5 was co-expressed with either RGS7 or RGS9, the acceleration of GIRK channel kinetics was strongly increased over that produced by RGS7 or RGS9 alone. RGS function was not enhanced by co-expression of Gbeta1, and co-expression of Gbeta5 alone had no effect on GIRK channel kinetics. Gbeta5 did not modulate the function either of RGS4, an RGS protein that lacks a GGL domain, or of a functional RGS7 construct in which the GGL domain was omitted. Enhancement of RGS7 function by Gbeta5 was not a consequence of an increase in the amount of plasma membrane or cytosolic RGS7 protein.
ESTHER : Kovoor_2000_J.Biol.Chem_275_3397
PubMedSearch : Kovoor_2000_J.Biol.Chem_275_3397
PubMedID: 10652332