scholarly journals Influenza H1N1 A/Solomon Island/3/06 Virus Receptor Binding Specificity Correlates with Virus Pathogenicity, Antigenicity, and Immunogenicity in Ferrets

2010 ◽  
Vol 84 (10) ◽  
pp. 4936-4945 ◽  
Author(s):  
Qi Xu ◽  
Weijia Wang ◽  
Xing Cheng ◽  
James Zengel ◽  
Hong Jin
Keyword(s):  
Sialic Acid ◽  
Respiratory Tract ◽  
Receptor Binding ◽  
Lower Respiratory Tract ◽  
Solomon Island ◽  
Influenza Viruses ◽  
Single Amino Acid ◽  
Wild Type ◽  
Single Amino Acid Change ◽  
The Impact

ABSTRACT Influenza viruses attach to cells via a sialic acid moiety (sialic acid receptor) that is α2-3 linked or α2-6 linked to galactose (α2-3SAL or α2-6SAL); sialic acid acts as a receptor for the virus. Using lectin staining, we demonstrated that the α2-6SAL configuration is predominant in the respiratory tract of ferrets, including trachea, bronchus, and lung alveolus tissues. Recombinant wild-type (rWT) influenza A/Solomon Island/3/06 (SI06) (H1N1) viruses were constructed to assess the impact of the hemagglutinin (HA) variations (amino acids 190 or 226) identified in natural variants on virus replication in the upper and lower respiratory tract of ferrets, as well as virus antigenicity and immunogenicity. A single amino acid change at residue 226 (from Gln to Arg) in the HA of SI06 resulted in the complete loss of binding to α2-6SAL and a concomitant loss of the virus's ability to replicate in the lower respiratory tract of ferrets. In contrast, the virus with Gln226 in the HA protein has a receptor binding preference for α2-6SAL and replicates efficiently in the lungs. There was a good correlation between viral replication in the lungs of ferrets and disease symptoms. In addition, we also showed that the 190 and 226 residues affected viral antigenicity and immunogenicity. Our data emphasize the necessity of thoroughly assessing wild-type influenza viruses for their suitability as reference strains and for carefully selecting the HA antigen for vaccine production during annual influenza vaccine evaluation processes.

scholarly journals A Single Amino Acid Substitution in 1918 Influenza Virus Hemagglutinin Changes Receptor Binding Specificity

2005 ◽  
Vol 79 (17) ◽  
pp. 11533-11536 ◽  
Author(s):  
Laurel Glaser ◽  
James Stevens ◽  
Dmitriy Zamarin ◽  
Ian A. Wilson ◽  
Adolfo García-Sastre ◽  
...  
Keyword(s):  
New York ◽  
Sialic Acid ◽  
Amino Acid ◽  
Receptor Binding ◽  
Consensus Sequence ◽  
Binding Specificity ◽  
Influenza Viruses ◽  
Single Amino Acid ◽  
1918 Influenza ◽  
Receptor Binding Specificity

ABSTRACT The receptor binding specificity of influenza viruses may be important for host restriction of human and avian viruses. Here, we show that the hemagglutinin (HA) of the virus that caused the 1918 influenza pandemic has strain-specific differences in its receptor binding specificity. The A/South Carolina/1/18 HA preferentially binds the α2,6 sialic acid (human) cellular receptor, whereas the A/New York/1/18 HA, which differs by only one amino acid, binds both the α2,6 and the α2,3 sialic acid (avian) cellular receptors. Compared to the conserved consensus sequence in the receptor binding site of avian HAs, only a single amino acid at position 190 was changed in the A/New York/1/18 HA. Mutation of this single amino acid back to the avian consensus resulted in a preference for the avian receptor.

scholarly journals Amino acid polymorphism at residue 222 of the receptor-binding site of the hemagglutinin of the pandemic influenza A(H1N1)pdm09 from patients 166 with lethal virus pneumonia in 2012-2014

2016 ◽  
Vol 61 (4) ◽  
pp. 166-171 ◽  
Author(s):  
K. G. Krasnoslobodtsev ◽  
D. K. Lvov ◽  
S. V. Alkhovsky ◽  
E. I. Burtseva ◽  
I. T. Fedyakina ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Receptor Binding ◽  
Lower Respiratory Tract ◽  
Influenza A ◽  
Viral Population ◽  
Wild Type ◽  
Binding Region ◽  
Influenza A H1n1 ◽  
Mutant Forms ◽  
Receptor Binding Region

Survey data from autopsy specimens from patients who died from pneumonia caused by the influenza A(H1N1) pdm09 in 2012-2014 and mutant forms of influenza virus in these patients (position 222 in the receptor-binding region of hemagglutinin) were presented. In total, according to aggregate data, obtained with three different methods (sequencing, next-generation sequencing (NGS), virus isolation) mutant viruses were detected in 17 (41%) from 41 patients. The proportion of the mutant forms in viral populations ranged from 1% to 69.2%. The most frequent mixture was the wild type (D222) and mutant (D222G), with proportion of mutant type ranged from 3.3% to 69.2% in the viral population. Mutation D222N (from 1.1% to 5.5%) was found rarely. Composition of the viral population from one patient is extremely heterogeneous: in left lung there was only wild type D222, meantime in right lung - mixture of mutant forms 222D/N/G (65.4/32.5/1.1%), in trachea - mixture 222D/G/Y/A (61.8/35.6/1.2/1.4%, respectively), and in bronchi compound of 222D/G/N/A (64.3/33.7/1/1%, respectively) were detected. The obtained data indicate that the process of adaptation of the virus in the lower respiratory tract is coupled with the appearance of different virus variants with mutations in the receptor-binding region. Mutant forms of the virus are observed in the lower respiratory tract of the majority of patients with lethal viral pneumonia. However, if they are a minor part of the population, they cannot be detected by the method of conventional sequencing. They can be identified using the NGS methods.

scholarly journals Vaccine-elicited antibody that neutralizes H5N1 influenza and variants binds the receptor site and polymorphic sites

2015 ◽  
Vol 112 (30) ◽  
pp. 9346-9351 ◽  
Author(s):  
Katie L. Winarski ◽  
Natalie J. Thornburg ◽  
Yingchun Yu ◽  
Gopal Sapparapu ◽  
James. E. Crowe ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Binding Site ◽  
Receptor Binding ◽  
Germ Line ◽  
Influenza Viruses ◽  
Antigenic Drift ◽  
Receptor Binding Site ◽  
Critical Feature ◽  
H5n1 Influenza ◽  
The Impact

Antigenic drift of circulating seasonal influenza viruses necessitates an international vaccine effort to reduce the impact on human health. A critical feature of the seasonal vaccine is that it stimulates an already primed immune system to diversify memory B cells to recognize closely related, but antigenically distinct, influenza glycoproteins (hemagglutinins). Influenza pandemics arise when hemagglutinins to which no preexisting adaptive immunity exists acquire the capacity to infect humans. Hemagglutinin 5 is one subtype to which little preexisting immunity exists and is only a few acquired mutations away from the ability to transmit efficiently between ferrets, and possibly humans. Here, we describe the structure and molecular mechanism of neutralization by H5.3, a vaccine-elicited antibody that neutralizes hemagglutinin 5 viruses and variants with expanded host range. H5.3 binds in the receptor-binding site, forming contacts that recapitulate many of the sialic acid interactions, as well as multiple peripheral interactions, yet is not sensitive to mutations that alter sialic acid binding. H5.3 is highly specific for a subset of H5 strains, and this specificity arises from interactions to the periphery of the receptor-binding site. H5.3 is also extremely potent, despite retaining germ line-like conformational flexibility.

scholarly journals Enhancement of the Efficiency of Secretion of Heterologous Lipase in Escherichia coli by Directed Evolution of the ABC Transporter System

2005 ◽  
Vol 71 (7) ◽  
pp. 3468-3474 ◽  
Author(s):  
Gyeong Tae Eom ◽  
Jae Kwang Song ◽  
Jung Hoon Ahn ◽  
Yeon Soo Seo ◽  
Joon Shick Rhee
Keyword(s):  
Escherichia Coli ◽  
Directed Evolution ◽  
Abc Transporter ◽  
Microtiter Plate ◽  
Single Amino Acid ◽  
Wild Type ◽  
E Coli ◽  
Single Amino Acid Change ◽  
Secretion Efficiency

ABSTRACT The ABC transporter (TliDEF) from Pseudomonas fluorescens SIK W1, which mediated the secretion of a thermostable lipase (TliA) into the extracellular space in Escherichia coli, was engineered using directed evolution (error-prone PCR) to improve its secretion efficiency. TliD mutants with increased secretion efficiency were identified by coexpressing the mutated tliD library with the wild-type tliA lipase in E. coli and by screening the library with a tributyrin-emulsified indicator plate assay and a microtiter plate-based assay. Four selected mutants from one round of error-prone PCR mutagenesis, T6, T8, T24, and T35, showed 3.2-, 2.6-, 2.9-, and 3.0-fold increases in the level of secretion of TliA lipase, respectively, but had almost the same level of expression of TliD in the membrane as the strain with the wild-type TliDEF transporter. These results indicated that the improved secretion of TliA lipase was mediated by the transporter mutations. Each mutant had a single amino acid change in the predicted cytoplasmic regions in the membrane domain of TliD, implying that the corresponding region of TliD was important for the improved and successful secretion of the target protein. We therefore concluded that the efficiency of secretion of a heterologous protein in E. coli can be enhanced by in vitro engineering of the ABC transporter.

scholarly journals Sum1p, the Origin Recognition Complex, and the Spreading of a Promoter-Specific Repressor in Saccharomyces cerevisiae

2005 ◽  
Vol 25 (14) ◽  
pp. 5920-5932 ◽  
Author(s):  
Patrick J. Lynch ◽  
Hunter B. Fraser ◽  
Elena Sevastopoulos ◽  
Jasper Rine ◽  
Laura N. Rusche
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Origin Recognition Complex ◽  
Single Amino Acid ◽  
Wild Type ◽  
Genomic Context ◽  
Functional Connection ◽  
Histone Tails ◽  
Repressive Chromatin ◽  
Single Amino Acid Change ◽  
Origin Recognition

ABSTRACT In Saccharomyces cerevisiae, Sum1p is a promoter-specific repressor. A single amino acid change generates the mutant Sum1-1p, which causes regional silencing at new loci where wild-type Sum1p does not act. Thus, Sum1-1p is a model for understanding how the spreading of repressive chromatin is regulated. When wild-type Sum1p was targeted to a locus where mutant Sum1-1p spreads, wild-type Sum1p did not spread as efficiently as mutant Sum1-1p did, despite being in the same genomic context. Thus, the SUM1-1 mutation altered the ability of the protein to spread. The spreading of Sum1-1p required both an enzymatically active deacetylase, Hst1p, and the N-terminal tail of histone H4, consistent with the spreading of Sum1-1p involving sequential modification of and binding to histone tails, as observed for other silencing proteins. Furthermore, deletion of the N-terminal tail of H4 caused Sum1-1p to return to loci where wild-type Sum1p acts, consistent with the SUM1-1 mutation increasing the affinity of the protein for H4 tails. These results imply that the spreading of repressive chromatin proteins is regulated by their affinities for histone tails. Finally, this study uncovered a functional connection between wild-type Sum1p and the origin recognition complex, and this relationship also contributes to mutant Sum1-1p localization.

Respiratory tract viruses

2020 ◽  
pp. 723-734
Author(s):  
Malik Peiris
Keyword(s):  
Respiratory Tract ◽  
Lower Respiratory Tract ◽  
Respiratory Infections ◽  
Influenza Viruses ◽  
Parainfluenza Viruses ◽  
Clinical Syndromes ◽  
Respiratory Tract Viruses ◽  
Syncytial Virus ◽  
Tract Infections ◽  
Viral Respiratory Infections

Viral respiratory infections, including coronavirus, rhinovirus, adenovirus, respiratory syncytial virus, human metapneumovirus, parainfluenza viruses, and influenza viruses, are a substantial cause of morbidity and mortality worldwide, most notably the COVID-19 pandemic. Transmission occurs through direct contact, contaminated fomites, and large airborne droplets, with long-range transmission by small particle aerosols reported in at least some instances of influenza and severe acute respiratory syndrome. Clinical syndromes affect the upper and/or lower respiratory tract, including coryza, pharyngitis, croup, bronchiolitis, and pneumonia. Each syndrome can potentially be caused by several viruses, and each respiratory virus can be associated with different clinical syndromes. Measles is a major cause of lower respiratory tract infections and fatality in tropical countries.

scholarly journals A Single Amino Acid Change in the Newcastle Disease Virus Fusion Protein Alters the Requirement for HN Protein in Fusion

2000 ◽  
Vol 74 (11) ◽  
pp. 5101-5107 ◽  
Author(s):  
Theresa A. Sergel ◽  
Lori W. McGinnes ◽  
Trudy G. Morrison
Keyword(s):  
Amino Acid ◽  
Cell Surface ◽  
Protein Expression ◽  
Newcastle Disease ◽  
Amino Acid Change ◽  
Syncytium Formation ◽  
Single Amino Acid ◽  
Fusion Activity ◽  
Wild Type ◽  
Single Amino Acid Change

ABSTRACT The role of a leucine heptad repeat motif between amino acids 268 and 289 in the structure and function of the Newcastle disease virus (NDV) F protein was explored by introducing single point mutations into the F gene cDNA. The mutations affected either folding of the protein or the fusion activity of the protein. Two mutations, L275A and L282A, likely interfered with folding of the molecule since these proteins were not proteolytically cleaved, were minimally expressed at the cell surface, and formed aggregates. L268A mutant protein was cleaved and expressed at the cell surface although the protein migrated slightly slower than wild type on polyacrylamide gels, suggesting an alteration in conformation or processing. L268A protein was fusion inactive in the presence or absence of HN protein expression. Mutant L289A protein was expressed at the cell surface and proteolytically cleaved at better than wild-type levels. Most importantly, this protein mediated syncytium formation in the absence of HN protein expression although HN protein enhanced fusion activity. These results show that a single amino acid change in the F1 portion of the NDV F protein can alter the stringent requirement for HN protein expression in syncytium formation.

scholarly journals A single amino acid change in CUP2 alters its mode of DNA binding.

1990 ◽  
Vol 10 (9) ◽  
pp. 4778-4787 ◽  
Author(s):  
C Buchman ◽  
P Skroch ◽  
W Dixon ◽  
T D Tullius ◽  
M Karin
Keyword(s):  
Amino Acid ◽  
Dna Binding ◽  
Binding Activity ◽  
Binding Domain ◽  
Single Amino Acid ◽  
Dna Binding Domain ◽  
Sequence Motifs ◽  
Wild Type ◽  
Mobility Shift ◽  
Single Amino Acid Change

CUP2 is a copper-dependent transcriptional activator of the yeast CUP1 metallothionein gene. In the presence of Cu+ and Ag+) ions its DNA-binding domain is thought to fold as a cysteine-coordinated Cu cluster which recognizes the palindromic CUP1 upstream activation sequence (UASc). Using mobility shift, methylation interference, and DNase I and hydroxyl radical footprinting assays, we examined the interaction of wild-type and variant CUP2 proteins produced in Escherichia coli with the UASc. Our results suggest that CUP2 has a complex Cu-coordinated DNA-binding domain containing different parts that function as DNA-binding elements recognizing distinct sequence motifs embedded within the UASc. A single-amino-acid substitution of cysteine 11 with a tyrosine results in decreased Cu binding, apparent inactivation of one of the DNA-binding elements and a dramatic change in the recognition properties of CUP2. This variant protein interacts with only one part of the wild-type site and prefers to bind to a different half-site from the wild-type protein. Although the variant has about 10% of wild-type DNA-binding activity, it appears to be completely incapable of activating transcription.

scholarly journals Role of Human Bocavirus Respiratory Tract Infection in Hematopoietic Cell Transplant Recipients

2020 ◽  
Author(s):  
Chikara Ogimi ◽  
Emily T Martin ◽  
Hu Xie ◽  
Angela P Campbell ◽  
Alpana Waghmare ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Lower Respiratory Tract ◽  
Hematopoietic Cell ◽  
Respiratory Pathogen ◽  
Human Bocavirus ◽  
Cell Transplant ◽  
Transplant Recipients ◽  
Hematopoietic Cell Transplant ◽  
Tract Infections ◽  
The Impact

Abstract Background Limited data exist regarding the impact of human bocavirus (BoV) in hematopoietic cell transplant (HCT) recipients. Methods In a longitudinal surveillance study among allogeneic HCT recipients, pre-HCT and weekly post-HCT nasal washes and symptom surveys were collected through day 100, then at least every 3 months through 1 year post-HCT at the Fred Hutchinson Cancer Research Center (2005–2010). Samples were tested by multiplex semiquantitative polymerase chain reaction (PCR) for 12 viruses. Plasma samples from BoV + subjects were analyzed by PCR. Separately, we conducted a retrospective review of HCT recipients with BoV detected in lower respiratory tract specimens. Results Among 51 children and 420 adults in the prospective cohort, 21 distinct BoV respiratory tract infections (RTIs) were observed by 1 year post-HCT in 19 patients. Younger age and exposure to children were risk factors for BoV acquisition. Univariable models among patients with BoV RTI showed higher peak viral load in nasal samples (P = .04) and presence of respiratory copathogens (P = .03) were associated with presence of respiratory symptoms, but BoV plasma detection was not. Only watery eyes and rhinorrhea were associated with BoV RTI in adjusted models. With additional chart review, we identified 6 HCT recipients with BoV detected in lower respiratory tract specimens (incidence rate of 0.4% [9/2509] per sample tested). Although all cases presented with hypoxemia, 4 had respiratory copathogens or concomitant conditions that contributed to respiratory compromise. Conclusions BoV RTI is infrequent in transplant recipients and associated with mild symptoms. Our studies did not demonstrate convincing evidence that BoV is a serious respiratory pathogen.

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