Identification of the roles of individual amino acid residues of the helix E of the major antenna of photosystem II (LHCII) by alanine scanning mutagenesis

2014 ◽  
Vol 156 (4) ◽  
pp. 203-210 ◽  
Author(s):  
Cheng Liu ◽  
Yan Rao ◽  
Lei Zhang ◽  
Chunhong Yang
Keyword(s):  
Amino Acid ◽  
Photosystem Ii ◽  
Individual Amino Acid ◽  
Amino Acid Residues ◽  
Alanine Scanning Mutagenesis ◽  
Alanine Scanning

scholarly journals Alanine scanning of dinitroaniline/phosphorothioamidate site of α-tubulin in plasmodium species distributed in India

2020 ◽  
Vol 26 ◽  
pp. 293-297
Author(s):  
O. M. Demchuk ◽  
P. A. Karpov ◽  
A. V. Rayevsky ◽  
S. P. Ozheredov ◽  
S. I. Spivak ◽  
...  
Keyword(s):  
Protein Structure ◽  
Amino Acid ◽  
Specific Binding ◽  
Plasmodium Species ◽  
Protein Docking ◽  
Amino Acid Residues ◽  
Alanine Scanning Mutagenesis ◽  
Alanine Scanning ◽  
Protein Structure Optimization ◽  
Dynamics Method

Aim. Identification of amino acid residues participating in specific binding of dinitroaniline and phosphorothioamidate compounds with α-tubulin in Plasmodium falciparum. Methods. Protein structure modelling, protein structure optimization using molecular dynamics method, ligand-protein docking, alanine scanning mutagenesis. Results. Molecular docking of canonical compounds and alanine scanning mutagenesis, indicate two key (Arg2, Val250) and one minor (Glu3) residues involved in binding of both - dinitroaniline and phosphorothioamidate compounds. At the same time, it was revealed two minor residues (Asp251, Glu254) interacting only with some members of dinitroaniline grope. Conclusions. It was identified amino acid residues predetermining existence of joint site and similar interaction of α-tubulin with dinitroani-line and phosphorothioamidate compounds in P. falciparum. Keywords: malaria, Plasmodium, α-tubulin, molecular interaction, dinitroanilines compounds, phosphorothioamidate compounds, alanine scanning mutagenesis.

Identification of Functionally Important Amino Acid Residues within the C2-Domain of Human Factor V Using Alanine-Scanning Mutagenesis†

Biochemistry ◽  
2000 ◽  
Vol 39 (8) ◽  
pp. 1951-1958 ◽  
Author(s):  
Suhng Wook Kim ◽  
Mary Ann Quinn-Allen ◽  
J. Terese Camp ◽  
Sandra Macedo-Ribeiro ◽  
Pablo Fuentes-Prior ◽  
...  
Keyword(s):  
Amino Acid ◽  
Human Factor ◽  
Factor V ◽  
C2 Domain ◽  
Amino Acid Residues ◽  
Alanine Scanning Mutagenesis ◽  
Alanine Scanning ◽  
Important Amino Acid

scholarly journals Regulation of AE2-mediated Cl− Transport by Intracellular or by Extracellular pH Requires Highly Conserved Amino Acid Residues of the AE2 NH2-terminal Cytoplasmic Domain

2002 ◽  
Vol 120 (5) ◽  
pp. 707-722 ◽  
Author(s):  
A.K. Stewart ◽  
M.N. Chernova ◽  
B.E. Shmukler ◽  
S. Wilhelm ◽  
S.L. Alper
Keyword(s):  
Amino Acid ◽  
Anion Exchange ◽  
Cytoplasmic Domain ◽  
Weak Acid ◽  
Extracellular Ph ◽  
Individual Amino Acid ◽  
Amino Acid Residues ◽  
General Importance ◽  
Alanine Scan ◽  
Intracellular Alkalinization

We reported recently that regulation by intracellular pH (pHi) of the murine Cl−/HCO3− exchanger AE2 requires amino acid residues 310–347 of the polypeptide's NH2-terminal cytoplasmic domain. We have now identified individual amino acid residues within this region whose integrity is required for regulation of AE2 by pH. 36Cl− efflux from AE2-expressing Xenopus oocytes was monitored during variation of extracellular pH (pHo) with unclamped or clamped pHi, or during variation of pHi at constant pHo. Wild-type AE2–mediated 36Cl− efflux was profoundly inhibited by acid pHo, with a value of pHo(50) = 6.87 ± 0.05, and was stimulated up to 10-fold by the intracellular alkalinization produced by bath removal of the preequilibrated weak acid, butyrate. Systematic hexa-alanine [(A)6]bloc substitutions between aa 312–347 identified the greatest acid shift in pHo(50) value, ∼0.8 pH units in the mutant (A)6342–347, but only a modest acid-shift in the mutant (A)6336–341. Two of the six (A)6 mutants retained normal pHi sensitivity of 36Cl− efflux, whereas the (A)6 mutants 318–323, 336–341, and 342–347 were not stimulated by intracellular alkalinization. We further evaluated the highly conserved region between aa 336–347 by alanine scan and other mutagenesis of single residues. Significant changes in AE2 sensitivity to pHo and to pHi were found independently and in concert. The E346A mutation acid-shifted the pHo(50) value to the same extent whether pHi was unclamped or held constant during variation of pHo. Alanine substitution of the corresponding glutamate residues in the cytoplasmic domains of related AE anion exchanger polypeptides confirmed the general importance of these residues in regulation of anion exchange by pH. Conserved, individual amino acid residues of the AE2 cytoplasmic domain contribute to independent regulation of anion exchange activity by pHo as well as pHi.

Structure - function analysis of photosystem II subunit S (PsbS) in vivo

2002 ◽  
Vol 29 (10) ◽  
pp. 1131 ◽  
Author(s):  
Xiao-Ping Li ◽  
Alba Phippard ◽  
Jae Pasari ◽  
Krishna K. Niyogi
Keyword(s):  
Amino Acid ◽  
Photosystem Ii ◽  
Function Analysis ◽  
Amino Acid Sequences ◽  
Forward Genetics ◽  
Photochemical Quenching ◽  
Amino Acid Residues ◽  
The Stability ◽  
Psbs Gene

In land plants, photosystem II subunit S (PsbS) plays a key role in xanthophyll- and pH-dependent non-photochemical quenching (qE) of excess absorbed light energy. Arabidopsis thaliana (L.) Heynh. npq4 mutants are defective in the psbS gene and have impaired qE. Exactly how the PsbS protein is involved in qE is unclear, but it has been proposed that PsbS binds H+ and/or de-epoxidized xanthophylls in excess light as part of the qE mechanism. To identify amino acid residues that are important for PsbS function, we sequenced the psbS gene from eight npq4 point mutant alleles isolated by forward genetics screening, including two new alleles. In the four transmembrane helices of PsbS, several amino acid residues were found to affect the stability and/or function of the protein. By comparing the predicted amino acid sequences of PsbS from several plant species and studying the proposed topological structure of PsbS, eight possible H+-binding amino acid residues on the lumenal side of the protein were identified and then altered by site-directed mutagenesis in vitro. The mutant psbS genes were transformed into npq4-1, a psbS deletion mutant, to test the stability and function of the mutant PsbS proteins in�vivo. The results demonstrate that two conserved, protonatable amino acids, E122 and E226, are especially critical for the function of PsbS.

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