• One hypothesis suggests that the virus crossed the species barrier from birds to humans in part due to critical mutations in the HA (H1 subtype) that changed the binding preference from the avian sialic acid (α2,3) linkage to the human (α2,6) form ( 1 , 12 , 23 ). (asm.org)
  • Mutations leading to hemophilia A by substitution of amino acids in coagulation factor VIII may provide important clues to the structure and function of this large and enigmatic protein. (biomedsearch.com)
  • The hemagglutination-inhibition assay revealed an evident impact of mutations at sites 88, 156, 205, 208, 239 and 289 to the HA antigenicity, and highlighted that the amino acid substitutions located in the antigenic region B, especially the combined mutations at sites 205 and 208, were the major antigenic determinant which was also consistent with results from flow cytometry and antigenic mapping. (flu.org.cn)
  • For comparison, consider the Jukes Cantor model, which is a Markov model of point mutations in nucleic acid sequences. (cmu.edu)
  • Mutations on W74, S237, S240, I247 and L266 in the extracellular loops 1 and 2 severely impaired the inhibitory effect of BzATP, indicating that they might be the essential amino acids in the putative binding site. (elsevier.com)
  • However, it has been controversial whether the functional divergence occurs by positive Darwinian selection that accelerates the fixation of advantageous mutations (largely nonsynonymous or amino acid-altering mutations) ( 6 ) or by random fixation of neutral mutations, which later induce a change in gene function when the environment or the genetic background is altered (Dykhuizen-Hartl effect) ( 7 , 8 ). (pnas.org)
  • DNA sequencing discovered two mutations at nt 353 (A to T) and nt 349 (T to A), leading to Thr to Met and Ser to Thr substitutions at aa 118 and 117 of HBsAg, respectively. (microbiologyresearch.org)
  • Results: S. pyogenes TU-296 was found to have the following mutations and amino acid substitutions: adenine 476 to cytosine in gyrA and cytosine 367 to thymine in parC, resulting in Glu-85→Ala in GyrA and Ser-79→Phe in ParC. (elsevier.com)
  • We present here a one-tube-only standardized SDM approach that generates comprehensive collections of amino acid substitution variants, including scanning- and single site-multiple mutations. (jesuscortes.info)
  • The PAM1 matrix is used as the basis for calculating other matrices by assuming that repeated mutations would follow the same pattern as those in the PAM1 matrix, and multiple substitutions can occur at the same site. (wikipedia.org)
  • It was found that the A281G substitution greatly affects the enzyme specificity and allows efficient activation of both polar and small aliphatic amino acids (serine, glycine and alanine), confirming predictions and conclusions based on molecular dynamics simulations. (rsc.org)
  • The valine, alanine, and glycine replacements were observed to be somewhat more destabilizing than serine, asparagine, and aspartic acid. (semanticscholar.org)
  • The reactive serine of the TGGHSL thioester binding motif of the first amino acid-activating domain of surfactin synthetase was replaced by alanine using site-directed mutagenesis. (elsevier.com)
  • The results show that l-Glu is acativated at the first domain of surfactin synthetase, and give further evidence that a serine residue is essential for substrate amino acid activation at the reaction centers of peptide synthetases. (elsevier.com)
  • By evaluating the genetic variability of HpHbR in a comprehensive geographical and taxonomic context, we show that a single substitution that replaces leucine with serine at position 210 is conserved in the most widespread form of Tbg (Tbg group 1) and not found in related taxa, which are either human serum susceptible (Tbb) or known to resist lysis via an alternative mechanism (Tbr and Tbg group 2). (unibas.ch)
  • Preliminary review of D222G amino acid substitution in the haemagglutinin of pandemic influenza A (H1N1) 2009 viruses. (nih.gov)
  • During the 2012/13 epidemic season in Spain, two A(H1N1)pdm09 viruses bearing the specific Y155H substitution in the NA were detected and isolated from two patients diagnosed with severe respiratory syndrome and pneumonia requiring admission to the intensive care unit. (eurosurveillance.org)
  • We believe that this report can contribute to a better understanding of the biological significance of amino acid substitutions in the neuraminidase protein with regard to susceptibility of influenza viruses to neuraminidase inhibitors. (eurosurveillance.org)
  • In general, human viruses preferentially interact with an N -acetylsialic acid attached to galactose with an α2,6 linkage (SAα2,6Gal), whereas avian viruses mostly bind to N- acetylsialic acid attached to galactose with an α2,3 linkage (SAα2,3Gal) ( 2 , 14 - 16 , 25 ). (asm.org)
  • In addition, as viruses adapt to a new host, the receptor binding can become more restricted to one type of sialic acid linkage ( 5 , 13 , 17 , 25 ). (asm.org)
  • Sequencing of the parental and derivative viruses (MNV-1.CW1.P1 and MNV-1.CW1.P3) identified two amino acid differences: a valine-to-isoleucine change in the nonstructural protein NS4 (G2151A) and a lysine-to-glutamate change in the VP1 capsid protein (A5941G) (Fig. 1A ). (asm.org)
  • An accumulation of amino acid substitutions in HA was observed in viruses derived from the late epidemic waves. (biomedcentral.com)
  • Moreover, PB2 E627K substitution was shared by the three mouse-adapted viruses (two viruses belong to YRD lineage and one virus belongs to PRD lineage), and PA T97A substitution was shared by two mouse-adapted viruses (belong to YRD lineage). (biomedcentral.com)
  • Although several general amino acid substitution models have been estimated from large and diverse protein databases, they remain inappropriate for analyzing specific species, e.g., viruses. (beds.ac.uk)
  • We propose an influenza-specific amino acid substitution model to enhance the understanding of the evolution of influenza viruses. (beds.ac.uk)
  • We demonstrate that a specialist herbivore minimizes the activation of defenses by converting an elicitor into an antagonist effector and identify an amino acid substitution that recovers these induced plant defenses to a level observed with generalist herbivores. (plantphysiol.org)
  • Here, we identify an amino acid substitution in COI that is universal among hummingbirds, rare and unfixed among other birds and vertebrates, and limited to a small set of disparate clades among metazoans. (g3journal.org)
  • PolyPhen-2 and SIFT had significantly lower accuracies in predicting the effects of amino acid substitutions outside CFDs than expected, with especially low sensitivity. (hindawi.com)
  • The optimal MHC class I presentable peptide length is most likely generated by N-terminal trimming by ER resident ( 19 , 20 , 21 ) or cytosolic amino peptidases, as has recently been suggested for the OVA CTL epitope ( 17 , 22 ). (jimmunol.org)
  • We show that when incorporated into the homology search algorithms BLAST and PSI-blaST, the structure-based substitution matrices enhance the efficacy of detecting remote homologs. (dovepress.com)
  • Based on homology with the pore loop of potassium channels, locations at which R substitution induces susceptibility to fatty acid inhibition face away from the cytoplasm toward the M1 and M3 helices and surrounding lipids. (rupress.org)
  • We constructed a mechanistic framework for modelling amino acid substitution rates that uses the formalisms of statistical mechanics, with principles of population genetics underlying the analysis. (datadryad.org)
  • The Y155H amino acid substitution in the neuraminidase gene (NA) has previously been associated with highly reduced inhibition by neuraminidase inhibitors in the seasonal H1N1 influenza A virus which circulated in humans before the 2009 pandemic. (eurosurveillance.org)
  • Nucleic Acids Res. (uchicago.edu)
  • This work will be extended and combined with new experimental data, including small and wide angle X-ray scattering and NMR, to develop and refine empirical modifications to a fixed charge nucleic acid force field. (nist.gov)
  • In vitro proteasome-mediated digestion analysis ( 12 , 13 , 15 , 17 ) and proteasome inhibitor studies ( 17 , 18 ) have shown that in particular the C terminus of the CTL epitope is precisely determined by the proteasome, whereas the N terminus is often elongated by one or two amino acids. (jimmunol.org)
  • In this report, we identify previously uncharacterized amino acids in the N terminus and the conserved core domain of Nef that are essential for the detection of Nef/kinase interactions as well as Nef phosphorylation during SIV infection. (elsevier.com)
  • Therefore, it is possible to distinguish between the two hypotheses by comparing the rates of synonymous and nonsynonymous substitution. (pnas.org)
  • Earlier studies ( 9 - 11 ) have indicated that the rate of nonsynonymous substitution is often enhanced after gene duplication, but in no case was the rate significantly higher than that of synonymous substitution, leaving the role of positive selection uncertain. (pnas.org)
  • Amino Acid Substitution" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (uchicago.edu)
  • The presence of an R467K amino acid substitution and loss of allelic variation correlate with an azole-resistant lanosterol 14alpha demethylase in Candida albicans. (asm.org)
  • Multiple regression analyses were performed correlating overall stability with the hydrophobicity, size, and helix propensity of the replacement amino acid. (rice.edu)
  • A single amino acid substitution (R467K) that occurred in isolate 13 was identified in both alleles of ERG16. (asm.org)
  • The specific activity of CYP51(R467K) for the release of formic acid from 3β-[32- 3 H]hydroxylanost-7-en-32-ol was 70 pmol/nmol of P450/min for microsomal protein compared to 240 pmol/nmol of P450/min for microsomal fractions expressing wild-type CYP51. (asm.org)