scholarly journals A two-amino acid insertion in the Cys146- Cys167 loop of the alphaIIb subunit is associated with a variant of Glanzmann thrombasthenia. Critical role of Asp163 in ligand binding.

1998 ◽  
Vol 102 (6) ◽  
pp. 1183-1192 ◽  
Author(s):  
S Honda ◽  
Y Tomiyama ◽  
M Shiraga ◽  
S Tadokoro ◽  
J Takamatsu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Ligand Binding ◽  
Critical Role ◽  
Glanzmann Thrombasthenia ◽  
Amino Acid Insertion

scholarly journals The role of amino acid α38 in the control of oxygen binding to human adult and embryonic haemoglobin Portland

1999 ◽  
Vol 343 (3) ◽  
pp. 681-685 ◽  
Author(s):  
Tao ZHENG ◽  
Thomas BRITTAIN ◽  
Nicholas J. WATMOUGH ◽  
Roy E. WEBER
Keyword(s):  
Amino Acid ◽  
Ligand Binding ◽  
Significant Contribution ◽  
Molecular Model ◽  
Site Directed Mutagenesis ◽  
Oxygen Binding ◽  
Naturally Occurring ◽  
Two State Model ◽  
T State

The role of the amino acid at position α38 in haemoglobin has been probed using site-directed mutagenesis. When the Thr residue at position α38 (which is totally conserved in all mammals) is changed to a Gln, the equilibrium properties of the protein are significantly altered. Equilibrium and kinetic data show that the R-state properties of the protein are essentially unaffected by the mutation whilst the allosteric equilibrium and T-state properties are changed. Mutation of the naturally occurring Gln38 of the human embryonic haemoglobin ζ-chain (the only known non-Thr containing globin) to a Thr residue shows the converse change in properties produced by the adult mutation, although in this case the situation is complicated by significant chain heterogeneity in the T state. An extension of the two-state model of co-operativity is presented to describe quantitatively the equilibrium ligand binding in the presence of T-state chain heterogeneity. A molecular model is described in which the putative interaction of αGln38 and βTyr145 is identified which make a significant contribution to the previously reported unusual ligand-binding properties of the ζ-chain containing human embryonic haemoglobins.

scholarly journals Critical role of ASCT2-mediated amino acid metabolism in promoting leukaemia development and progression

2019 ◽  
Vol 1 (3) ◽  
pp. 390-403 ◽  
Author(s):  
Fang Ni ◽  
Wen-Mei Yu ◽  
Zhiguo Li ◽  
Douglas K. Graham ◽  
Lingtao Jin ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Critical Role

scholarly journals Role of the amino acid residues in the exogeneous ligand binding to an NO carrier protein, NP4.

2003 ◽  
Vol 43 (supplement) ◽  
pp. S86
Author(s):  
T. Uno ◽  
Y. Hamabe ◽  
Y. Moriyama ◽  
Y. Tomisugi ◽  
Y. Ishikawa
Keyword(s):  
Amino Acid ◽  
Ligand Binding ◽  
Carrier Protein ◽  
Amino Acid Residues

scholarly journals Critical role of amino acid position 343 of surfactant protein-D in the selective binding of glycolipids from Mycobacterium tuberculosis

Glycobiology ◽  
2009 ◽  
Vol 19 (12) ◽  
pp. 1473-1484 ◽  
Author(s):  
Tracy K Carlson ◽  
Jordi B Torrelles ◽  
Kelly Smith ◽  
Tim Horlacher ◽  
Riccardo Castelli ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Amino Acid ◽  
Critical Role ◽  
Amino Acid Position ◽  
Surfactant Protein ◽  
Surfactant Protein D ◽  
Selective Binding

scholarly journals Insights into the mysterious genetic variation profile oftprKinTreponema pallidumunder the development of natural human syphilis infection

2019 ◽  
Author(s):  
Dan Liu ◽  
Man-Li Tong ◽  
Yong Lin ◽  
Li-Li Liu ◽  
Li-Rong Lin ◽  
...  
Keyword(s):  
Amino Acid ◽  
Immune Evasion ◽  
High Frequency ◽  
Critical Role ◽  
Treponema Pallidum ◽  
Secondary Syphilis ◽  
Human Infection ◽  
Amino Acid Sequences ◽  
Potential Vaccine

AbstractAlthough the variations of thetprKgene inTreponema pallidumwere considered to play a critical role in the pathogenesis of syphilis, how actual variable characteristics oftprKin the course of natural human infection enabling the pathogen’s survive has thus far remained unclear. Here, we performed NGS to investigatetprKofT. pallidumdirectly from primary and secondary syphilis samples. Compared with diversity intprKof the strains from primary syphilis samples, there were more mixture variants found within seven V regions of thetprKgene among the strains from secondary syphilis samples, and the frequencies of predominant sequences within V regions oftprKwere generally decreased (less than 80%) with the proportion of minor variants in 10-60% increasing. Noteworthy, the variations within V regions oftprKalways obeyed a strict 3 bp changing pattern. AndtprKin the strains from the two-stage samples kept some stable amino acid sequences within V regions. Particularly, the amino acid sequences IASDGGAIKH and IASEDGSAGNLKH in V1 not only presented a high proportion of inter-population sharing, but also presented a relatively high frequency (above 80%) in the populations. Besides,tprKalways demonstrated remarkable variability in V6 at both the intra- and inter-strain levels regardless of the course. These findings unveiled that the different profile oftprK in T. pallidumdirectly from primary and secondary syphilis samples, indicating that throughout the development of syphilisT. pallidumconstantly varies its domaintprKgene to obtain the best adaptation to the host. While this changing was always subjected a strict gene conversion mechanism to keep an abnormal TprK. The highly stable peptides found in V1 would probably be promising potential vaccine components. And the highly heterogenetic regions (e.g. V6) could provide insight into the mysterious role oftprKin immune evasion.Author summaryAlthough the variations of thetprKgene inTreponema pallidumwere considered to play a critical role in the pathogenesis of syphilis, how actual variable characteristics oftprKin the course of natural human infection enabling the pathogen’s survive has thus far remained unclear. Here, we performed next-generation sequencing, a more sensitive and reliable approach, to investigatetprKofTreponema pallidumdirectly from primary and secondary syphilis patients, revealing that the profile oftprKinT. pallidumfrom the two-stage samples was different. Within the strains from secondary syphilis patients, more mixture variants within seven V regions oftprKwere found, the frequencies of their predominant sequences were generally decreased with the proportion of minor variants in 10-60% was increased. And the variations within V regions oftprKalways obeyed a strict 3 bp changing pattern. Noteworthy, the amino acid sequences IASDGGAIKH and IASEDGSAGNLKH in V1 presented a high proportion of inter-population sharing and presented a relatively high frequency in the populations. And V6 region always demonstrated remarkable variability at intra- and inter-patient levels regardless of the course. These findings provide insights into the mysterious role of TprK in immune evasion and for further exploring the potential vaccine components.

scholarly journals Identification of the amino acid residue responsible for the myricetin sensitivity of human proton-coupled folate transporter

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Takahiro Yamashiro ◽  
Tomoya Yasujima ◽  
Kinya Ohta ◽  
Katsuhisa Inoue ◽  
Hiroaki Yuasa
Keyword(s):  
Amino Acid ◽  
Amino Acid Residue ◽  
Potential Risk ◽  
Critical Role ◽  
Initial Analysis

AbstractHuman proton-coupled folate transporter (hPCFT/SLC46A1) has recently been found to be inhibited by myricetin by a sustained mechanism, raising a concern that the inhibition might lead to malabsorption of folates in the intestine, where hPCFT works for their epithelial uptake. However, rat PCFT (rPCFT) has more recently been found not to be inhibited by myricetin. Prompted by this finding, we attempted to determine the amino acid residue involved in that by analyses comparing between hPCFT and rPCFT. In the initial analysis, chimeric constructs prepared from hPCFT and rPCFT were examined for myricetin sensitivity to determine the hPCFT segment involved in the sensitivity. Focusing on the thereby determined segment from 83rd to 186th amino acid residue, hPCFT mutants having a designated amino acid residue replaced with its counterpart in rPCFT were prepared for the subsequent analysis. Among them, only G158N-substituted hPCFT was found to be transformed to be insensitive to myricetin and, accordingly, oppositely N158G-substituted rPCFT was transformed to be sensitive to myricetin. These results indicate the critical role of Gly158 in the myricetin sensitivity of hPCFT. This finding would help advance the elucidation of the mechanism of the myricetin-induced inhibition of hPCFT and manage the potential risk arising from that.

Sign in / Sign up

Export Citation Format

Share Document