Conservation of charge
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Previous structural andmutagenesis studies indicate that the invariant a-amino and a-carboxyl groups of glutamate receptor agonists are engaged in polar interactions with oppositely charged, conserved arginine and glutamate resi-dues in the ligand-binding domain ofa-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor.To examine the role of these residues (R507 and E727 in the GluR-D subunit) in the discrimination between agonists and anta-gonists, we analyzed the ligand-binding properties of homomeric GluR-D and its soluble ligand-binding domain withmutations at thesepositions....
10p tumor12 22-04-2013 38 3 Download
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The relevance of functional amino acids for taurocholate transport by the sodium-dependent taurocholate cotrans-porting polypeptide Ntcp was determined by site-directed mutagenesis. cRNAfrom28 single-pointsmutants of the rat liver Ntcp clone was expressed in Xenopus laevisoocytes.
11p tumor12 20-04-2013 46 5 Download
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Glycoside hydrolysis by retaining family 18 chitinases involves a catalytic acid (Glu) which is part of a conserved DXDXEsequence motif that spans strand four of a (ba)8 barrel (TIMbarrel) structure.Theseglycosidehydrolases are unusual in that thepositive charge emergingon theanomeric carbon after departure of the leaving group is stabilized by the substrate itself (the N-acetyl group of the distorted )1 sugar), rather than by a carboxylate group on the enzyme.
10p dell39 03-04-2013 35 3 Download
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The charged quaternary ammonium compounds – methyl, ethyl and benzyl viologens – generate reactive oxygen species in photosynthetic cells. Three independent methyl viologen-resistant spontaneous mutants of Synechocys-tis sp. PCC 6803 were identified, in which the conserved R115 residue of the Slr1174 protein was replaced with G115, L115 and C115. The Slr1174 protein of the DUF990 family is related to the permease subunit of an ABC-2-type transporter and its R115 mutation was found to be solely responsible for the observed methyl viologen resistance. ...
11p vinaphone15 25-02-2013 30 2 Download
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Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: Conserved charged amino acid residues in the extracellular region of sodium/iodide symporter are critical for iodide transport activity
9p toshiba23 18-11-2011 46 2 Download