scholarly journals Identification of amino acid residues that determine the substrate specificity of mammalian membrane-bound front-end fatty acid desaturases

2015 ◽  
Vol 57 (1) ◽  
pp. 89-99 ◽  
Author(s):  
Kenshi Watanabe ◽  
Makoto Ohno ◽  
Masahiro Taguchi ◽  
Seiji Kawamoto ◽  
Kazuhisa Ono ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Amino Acid ◽  
Substrate Specificity ◽  
Amino Acid Residues ◽  
Fatty Acid Desaturases ◽  
Front End ◽  
Membrane Bound

Prediction of amino acid residues participated in substrate recognition by cytochrome P450 subfamilies with broad substrate specificity

2013 ◽  
Vol 26 (2) ◽  
pp. 86-91 ◽  
Author(s):  
Maria S. Zharkova ◽  
Boris N. Sobolev ◽  
Nina Yu. Oparina ◽  
Alexander V. Veselovsky ◽  
Alexander I. Archakov
Keyword(s):  
Cytochrome P450 ◽  
Amino Acid ◽  
Substrate Specificity ◽  
Substrate Recognition ◽  
Amino Acid Residues ◽  
Broad Substrate Specificity

scholarly journals Plastidic Δ6 Fatty-Acid Desaturases with Distinctive Substrate Specificity Regulate the Pool of C18-PUFAs in the Ancestral Picoalga Ostreococcus tauri

2020 ◽  
Vol 184 (1) ◽  
pp. 82-96
Author(s):  
Charlotte Degraeve-Guilbault ◽  
Rodrigo E. Gomez ◽  
Cécile Lemoigne ◽  
Nattiwong Pankansem ◽  
Soizic Morin ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Substrate Specificity ◽  
Fatty Acid Desaturases ◽  
Ostreococcus Tauri

scholarly journals Gene Cloning and Molecular Characterization of Lysine Decarboxylase from Selenomonas ruminantiumDelineate Its Evolutionary Relationship to Ornithine Decarboxylases from Eukaryotes

2000 ◽  
Vol 182 (23) ◽  
pp. 6732-6741 ◽  
Author(s):  
Yumiko Takatsuka ◽  
Yoshihiro Yamaguchi ◽  
Minenobu Ono ◽  
Yoshiyuki Kamio
Keyword(s):  
Amino Acid ◽  
Substrate Specificity ◽  
Pyridoxal Phosphate ◽  
Evolutionary Relationship ◽  
Binding Domain ◽  
Sequencing Analysis ◽  
Lysine Decarboxylase ◽  
Amino Acid Residues ◽  
Phosphate Binding ◽  
Link Type

ABSTRACT Lysine decarboxylase (LDC; EC 4.1.1.18 ) from Selenomonas ruminantium comprises two identical monomeric subunits of 43 kDa and has decarboxylating activities toward both l-lysine andl-ornithine with similar Km andVmax values (Y. Takatsuka, M. Onoda, T. Sugiyama, K. Muramoto, T. Tomita, and Y. Kamio, Biosci. Biotechnol. Biochem. 62:1063–1069, 1999). Here, the LDC-encoding gene (ldc) of this bacterium was cloned and characterized. DNA sequencing analysis revealed that the amino acid sequence of S. ruminantium LDC is 35% identical to those of eukaryotic ornithine decarboxylases (ODCs; EC 4.1.1.17 ), including the mouse,Saccharomyces cerevisiae, Neurospora crassa,Trypanosoma brucei, and Caenorhabditis elegansenzymes. In addition, 26 amino acid residues, K69, D88, E94, D134, R154, K169, H197, D233, G235, G236, G237, F238, E274, G276, R277, Y278, K294, Y323, Y331, D332, C360, D361, D364, G387, Y389, and F397 (mouse ODC numbering), all of which are implicated in the formation of the pyridoxal phosphate-binding domain and the substrate-binding domain and in dimer stabilization with the eukaryotic ODCs, were also conserved inS. ruminantium LDC. Computer analysis of the putative secondary structure of S. ruminantium LDC showed that it is approximately 70% identical to that of mouse ODC. We identified five amino acid residues, A44, G45, V46, P54, and S322, within the LDC catalytic domain that confer decarboxylase activities toward bothl-lysine and l-ornithine with a substrate specificity ratio of 0.83 (defined as thek cat/Km ratio obtained with l-ornithine relative to that obtained withl-lysine). We have succeeded in converting S. ruminantium LDC to form with a substrate specificity ratio of 58 (70 times that of wild-type LDC) by constructing a mutant protein, A44V/G45T/V46P/P54D/S322A. In this study, we also showed that G350 is a crucial residue for stabilization of the dimer in S. ruminantium LDC.

scholarly journals The C-Terminal Hydrophobic Domain of Hepatitis C Virus RNA Polymerase NS5B Can Be Replaced with a Heterologous Domain of Poliovirus Protein 3A

2006 ◽  
Vol 80 (22) ◽  
pp. 11343-11354 ◽  
Author(s):  
Haekyung Lee ◽  
Ying Liu ◽  
Edison Mejia ◽  
Aniko V. Paul ◽  
Eckard Wimmer
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Amino Acid ◽  
Rna Polymerase ◽  
Decisive Role ◽  
Amino Acid Residues ◽  
Subgenomic Replicon ◽  
Hydrophobic Domain ◽  
Virus Rna ◽  
Membrane Bound

ABSTRACT Replication of the plus-stranded RNA genome of hepatitis C virus (HCV) occurs in a membrane-bound replication complex consisting of viral and cellular proteins and viral RNA. NS5B, the RNA polymerase of HCV, is anchored to the membranes via a C-terminal 20-amino-acid-long hydrophobic domain, which is flanked on each side by a highly conserved positively charged arginine. Using a genotype 1b subgenomic replicon (V. Lohmann, F. Korner, J. O. Koch, U. Herian, L. Theilmann, and R. Bartensclager, Science 285:110-113, 1999), we determined the effect of mutations of some highly conserved residues in this domain. The replacement of arginine 570 with alanine completely abolished the colony-forming ability by the replicon, while a R591A change was found to be highly detrimental to replication, viability, and membrane binding by the mutant NS5B protein. Mutations of two other highly conserved amino acids (L588A and P589A) reduced but did not eliminate colony formation. It was of interest, if specific amino acid residues play a role in membrane anchoring of NS5B and replication, to determine whether a complete exchange of the NS5B hydrophobic domain with a domain totally unrelated to NS5B would ablate replication. We selected the 22-amino-acid-long hydrophobic domain of poliovirus polypeptide 3A that is known to adopt a transmembrane configuration, thereby anchoring 3A to membranes. Surprisingly, either partial or full replacement of the NS5B hydrophobic domain with the anchor sequences of poliovirus polypeptide 3A resulted in the replication of replicons whose colony-forming abilities were reduced compared to that of the wild-type replicon. Upon continued passage of the replicon in Huh-7 cells in the presence of neomycin, the replication efficiency of the replicon increased. However, the sequence of the poliovirus polypeptide 3A hydrophobic domain, in the context of the subgenomic HCV replicon, was stably maintained throughout 40 passages. Our results suggest that anchoring NS5B to membranes is necessary but that the amino acid sequence of the anchor per se does not require HCV origin. This suggests that specific interactions between the NS5B hydrophobic domain and other membrane-bound factors may not play a decisive role in HCV replication.

scholarly journals Amino Acid Residues Involved in the Substrate Specificity of TauT/SLC6A6 for Taurine and γ-Aminobutyric Acid

2014 ◽  
Vol 37 (5) ◽  
pp. 817-825 ◽  
Author(s):  
Tohru Yahara ◽  
Masanori Tachikawa ◽  
Shin-ichi Akanuma ◽  
Yoshiyuki Kubo ◽  
Ken-ichi Hosoya
Keyword(s):  
Amino Acid ◽  
Substrate Specificity ◽  
Aminobutyric Acid ◽  
Amino Acid Residues
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