scholarly journals Positive Charges on Lysine Residues of the Extrinsic 18 kDa Protein Are Important to Its Electrostatic Interaction with Spinach Photosystem II Membranes

2005 ◽  
Vol 37 (11) ◽  
pp. 737-742 ◽  
Author(s):  
Jin-Peng Gao ◽  
Zhen-Hua Yong ◽  
Feng Zhang ◽  
Kang-Cheng Ruan ◽  
Chun-He Xu ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Methyl Esters ◽  
Binding Activity ◽  
Water Soluble ◽  
Carboxyl Groups ◽  
Amino Groups ◽  
Charged Amino Acids ◽  
Lysine Residues ◽  
Glycine Methyl Ester ◽  
Positively Charged

Abstract To determine the contribution of charged amino acids to binding with the photosystem II complex (PSII), the amino or carboxyl groups of the extrinsic 18 kDa protein were modified with Nsuccinimidyl propionate (NSP) or glycine methyl ester (GME) in the presence of a water-soluble carbodiimide, respectively. Based on isoelectric point shift, 4–10 and 10–14 amino groups were modified in the presence of 2 and 4 mM NSP, respectively. Similarly, 3–4 carboxyl groups were modified by reaction with 100 mM GME. Neutralization of negatively charged carboxyl groups with GME did not alter the binding activity of the extrinsic 18 kDa protein. However, the NSP-modified 18 kDa protein, in which the positively charged amino groups had been modified to uncharged methyl esters, failed to bind with the PSII membrane in the presence of the extrinsic 23 kDa protein. This defect can not be attributed to structural or conformational alterations imposed by chemical modification, as the fluorescence and circular dichroism spectra among native, GME and NSP-modified extrinsic 18 kDa proteins were similar. Thus, we have concluded that the positive charges of lysyl residues in the extrinsic 18 kDa protein are important for its interaction with PSII membranes in the presence of the extrinsic 23 kDa protein. Furthermore, it was found that the negative charges of carboxyl groups of this protein did not participate in binding with the extrinsic 23 kDa protein associated with PSII membranes.

scholarly journals Interaction of cartilage proteoglycans with hyaluronic acid. The role of the hyaluronic acid carboxyl groups

1977 ◽  
Vol 167 (3) ◽  
pp. 711-716 ◽  
Author(s):  
J E Christner ◽  
M L Brown ◽  
D D Dziewiatkowski
Keyword(s):  
Hyaluronic Acid ◽  
Methyl Ester ◽  
Binding Capacity ◽  
Methyl Esters ◽  
Binding Activity ◽  
Carboxyl Groups ◽  
Nasal Cartilage ◽  
Carboxylate Groups ◽  
Glycine Methyl Ester ◽  
Cartilage Proteoglycans

Hyaluronic acid-derived oligomers of five to fifteen repeat dissaccharides effectively bind to bovine nasal-cartilage proteoglycan and inhibit the interaction between proteoglycans and high-molecular-weight hyaluronic acid. If, however, the hyaluronic acid oligosaccharides are modified by reaction with diazomethane to form the carboxyl methyl esters of the glucuronic acid residues, their inhibitory activity is abolished. The binding capacity can be fully restored by saponification. The amide derivative, which is formed by condensation of the oligosaccharide carboxyl groups with glycine methyl ester, is also ineffective in blocking the proteoglycan-hyaluronic acid interaction. In this case, binding activity is not restored when the amidated oligomers are subjected to saponification to yield the free carboxylate groups on the glycine residues. Thus the displacement of the carboxylate groups on the polysaccharide chain by the interposition of a glycine residue blocks the interaction between the proteoglycans and the hyaluronic acid oligomers. When the oligosaccharide methyl ester is reduced with NaBH4, the resultant glucose-containing oligomers exhibit decreased binding to proteoglycans. Thus it appears that the hyaluronic acid carboxylate anion in a specific spatial orientation is required for hyaluronic acid-proteoglycan interaction.

Specific water-soluble substrates for chymotrypsin: Attempts for compensating diminished P1-S1 interactions

1988 ◽  
Vol 53 (11) ◽  
pp. 2884-2889 ◽  
Author(s):  
Volker Schellenberger ◽  
Ute Schellenberger ◽  
Hans-Dieter Jakubke
Keyword(s):  
Amino Acid ◽  
Methyl Esters ◽  
Water Soluble ◽  
Amino Acid Residues ◽  
Substrate Properties ◽  
Ester Moiety ◽  
Benzyl Esters ◽  
Peptide Esters ◽  
Acyl Donors ◽  
Positively Charged

N-Maleyl-L-amino acid and peptide esters were synthesized and employed as substrates for α-chymotrypsin. From the kcat/KM values can be suggested that benzyl esters are significantly better substrates than the appropriate methyl esters. Further improvement in the substrate properties results from the introduction of the p-nitrobenzyl ester moiety. The choline ester of benzyloxycarbonyl-L-phenylalanine with the highest kcat/KM value confirmed the P1' leaving group specificity for positively charged residues. From the kinetic data can be concluded that acyl donors with high kcat/KM values, which are useful in kinetically controlled enzymatic peptide synthesis, need not contain aromatic amino acid residues in the P1 position.

Sequence Determination of a Protein with N-Terminal Glutamic Acid after Modification of Carboxyl Groups with Carbodiimide as the Coupling Agent

1974 ◽  
Vol 52 (6) ◽  
pp. 560-562
Author(s):  
C. Gilardeau ◽  
M. Chrétien
Keyword(s):  
Methyl Ester ◽  
Glutamic Acid ◽  
Water Soluble ◽  
Carboxyl Groups ◽  
Edman Degradation ◽  
Sequence Determination ◽  
Glutamic Acid Residue ◽  
N Terminus ◽  
Glycine Methyl Ester

Glutamine and asparagine residues in proteins can be differentiated from glutamic and aspartic residues, during the Edman degradation, after modification of the carboxyl groups by glycine methyl ester in presence of a water-soluble carbodiimide. When applied to ovine and porcine beta-lipotropic hormones, which have a glutamic acid residue at the N-terminus, the carbodiimide blocks the N-terminus. However, the Edman degradation proceeds normally, if the phenylthiocarbamyl derivative is formed prior to the modification reaction with glycine. In this communication, radioactive glycine was used to modify the carboxyl groups.

scholarly journals Lysine Residues in the MK-Rich Region Are Not Required for Binding of the PbsP Protein From Group B Streptococci to Plasminogen

2021 ◽  
Vol 11 ◽  
Author(s):  
Francesco Coppolino ◽  
Letizia Romeo ◽  
Giampiero Pietrocola ◽  
Germana Lentini ◽  
Giuseppe Valerio De Gaetano ◽  
...  
Keyword(s):  
Binding Sites ◽  
Invasive Infection ◽  
Group B Streptococci ◽  
Rich Domain ◽  
Charged Amino Acids ◽  
Lysine Residues ◽  
Group B ◽  
Host Tissues ◽  
Positively Charged ◽  
Bacterial Sequence

Binding to plasminogen (Plg) enables bacteria to associate with and invade host tissues. The cell wall protein PbsP significantly contributes to the ability of group B streptococci, a frequent cause of invasive infection, to bind Plg. Here we sought to identify the molecular regions involved in the interactions between Plg and PbsP. The K4 Kringle domain of the Plg molecule was required for binding of Plg to whole PbsP and to a PbsP fragment encompassing a region rich in methionine and lysine (MK-rich domain). These interactions were inhibited by free L-lysine, indicating the involvement of lysine binding sites in the Plg molecule. However, mutation to alanine of all lysine residues in the MK-rich domain did not decrease its ability to bind Plg. Collectively, our data identify a novel bacterial sequence that can interact with lysine binding sites in the Plg molecule. Notably, such binding did not require the presence of lysine or other positively charged amino acids in the bacterial receptor. These data may be useful for developing alternative therapeutic strategies aimed at blocking interactions between group B streptococci and Plg.

Synthesis of pressinoic acid by enzymatically catalyzed formation of peptide bonds

1986 ◽  
Vol 51 (6) ◽  
pp. 1352-1360 ◽  
Author(s):  
Václav Čeřovský
Keyword(s):  
Methyl Esters ◽  
Sulfhydryl Group ◽  
Carboxyl Groups ◽  
Amino Groups ◽  
Peptide Bonds ◽  
Fragment Condensation

Three fully enzymatic syntheses of the 1-6 vasopressin hexapeptide were investigated using papain, α-chymotrypsin and thermolysin. Best results were obtained with thermolysin in the 2 + 4 fragment condensation. The α-chymotrypsin-catalyzed 3 + 3 condensation is less advantageous and the 4 + 2 condensation with papain gave only low yield. Using the mentioned enzymes, further fragments of vasopressin molecule were prepared. Amino groups were protected with benzoylcarbonyl or tert-butyloxycarbonyl groups, carboxyl groups as phenylhydrazides or methyl esters, and the cysteine sulfhydryl group as the benzyl derivate. The tyrosine hydroxyl was not protected.

scholarly journals Relationship between isoelectric point of native and chemically modified insulin and liposomal fusion

1989 ◽  
Vol 264 (1) ◽  
pp. 285-287 ◽  
Author(s):  
R N Farías ◽  
A E López Viñals ◽  
E Posse ◽  
R D Morero
Keyword(s):  
Methyl Ester ◽  
Isoelectric Point ◽  
Carboxyl Groups ◽  
Amino Groups ◽  
Chemically Modified ◽  
Glycine Methyl Ester ◽  
Native Insulin ◽  
Ph Range ◽  
Hydrolysis Of ◽  
Fusion Ability

Native insulin causes fusion of negatively charged liposomes in the pH range from 3.0 to 5.5. In marked contrast, insulin with all three amino groups succinylated did not show fusion ability at any pH. On the other hand, insulin amidated with glycine methyl ester with all six carboxyl groups blocked shifted its activity to higher pH, showing a pH range of activity from 3.0 to 7.4. When the carboxyl groups were recovered by hydrolysis of methoxyl groups from glycine methyl ester-treated insulin, the protein obtained (glycyl-insulin with six free carboxyl groups) behaved as native insulin. A good correlation between the isoelectric point values of insulin and its derivatives and their fusion properties was found.

scholarly journals Calcium binding by human erythrocyte membranes. Significance of carboxyl, amino and thiol groups

1971 ◽  
Vol 125 (1) ◽  
pp. 343-352 ◽  
Author(s):  
Janet Forstner ◽  
J. F. Manery
Keyword(s):  
Glutamic Acid ◽  
Aspartic Acid ◽  
Calcium Binding ◽  
Major Effect ◽  
Water Soluble ◽  
Erythrocyte Membranes ◽  
Molar Ratio ◽  
Carboxyl Groups ◽  
Amino Groups ◽  
Free Carboxyl

1. The role of the ionized carboxyl groups of proteins of the erythrocyte membrane as Ca2+ receptor sites was investigated. A water-soluble carbodi-imide [1-cyclohexyl-3-(2-morpholinoethyl)carbodi-imide methotoluene-p-sulphonate], referred to as carbodi-imide reagent, and glycine methyl ester were used to modify the free carboxyl groups of the membrane. The degree of modification was estimated from amino acid analyses, which showed the amount of glycine incorporated. As the concentration of carbodi-imide reagent was raised (0.1–0.4m) incorporation of glycine increased and Ca2+ binding decreased by about 77%. At 0.4m-carbodi-imide reagent all of the binding of Ca2+ to protein was abolished and it was estimated that about 37% of the side-chain carboxyl groups of aspartic acid plus glutamic acid had been blocked by glycine. 2. Acetylation of all of the free amino groups was achieved by incubating the erythrocyte ‘ghosts’ at pH10.3 with acetic anhydride (10–15mg/10mg of ‘ghost’ protein). Acetylation increased by 1.5-fold the capacity of the ‘ghost’ to bind Ca2+, indicating that the remaining carboxyl groups of aspartic acid and glutamic acid were made available for Ca2+ binding by this procedure. These findings support the concept that in normal ‘ghosts’, at pH7.4, Ca2+ binding to free carboxyl groups is partially hindered by the presence of charged amino groups. 3. Treatment of ‘ghosts’ with N-acetylneuraminidase, which removed 94% of sialic acid residues, and treatment with 1mm-p-chloromercuribenzoate did not alter Ca2+ binding. The major effect of 5.8mm-p-chloromercuribenzoate upon ‘ghosts’ was to cause a solubilization of a calcium–membrane complex, which included about one-third of the ‘ghosts’ protein. The molar ratio of Ca2+: protein in the solubilized material was the same as that in the intact (untreated) ‘ghosts’.

scholarly journals Hydroxyapatite formation on graphene oxide modified with amino acids: arginine versus glutamic acid

2016 ◽  
Vol 13 (114) ◽  
pp. 20150986 ◽  
Author(s):  
M. Tavafoghi ◽  
N. Brodusch ◽  
R. Gauvin ◽  
M. Cerruti
Keyword(s):  
Amino Acids ◽  
Graphene Oxide ◽  
Amino Groups ◽  
Phosphorylated Proteins ◽  
Charged Amino Acids ◽  
Simulated Body Fluids ◽  
The Individual ◽  
Local Supersaturation ◽  
Positively Charged ◽  
Hydroxyapatite Formation

Hydroxyapatite (HA, Ca 5 (PO 4 ) 3 OH) is the main inorganic component of hard tissues, such as bone and dentine. HA nucleation involves a set of negatively charged phosphorylated proteins known as non-collagenous proteins (NCPs). These proteins attract Ca 2+ and PO 4 3− ions and increase the local supersaturation to a level required for HA precipitation. Polar and charged amino acids (AAs) are highly expressed in NCPs, and seem to be responsible for the mineralizing effect of NCPs; however, the individual effect of these AAs on HA mineralization is still unclear. In this work, we investigate the effect of a negatively charged (Glu) and positively charged (Arg) AA bound to carboxylated graphene oxide (CGO) on HA mineralization in simulated body fluids (SBF). Our results show that Arg induces HA precipitation faster and in larger amounts than Glu. We attribute this to the higher stability of the complexes formed between Arg and Ca 2+ and PO 4 3− ions, and also to the fact that Arg exposes both carboxyl and amino groups on the surface. These can electrostatically attract both Ca 2+ and PO 4 3− ions, thus increasing local supersaturation more than Glu, which exposes carboxyl groups only.

Lipotropic and Adrenocorticotropic Hormones. Biological Activities of the Carboxyl-Modified Hormones

1974 ◽  
Vol 52 (3) ◽  
pp. 723-726 ◽  
Author(s):  
C. Gilardeau ◽  
M. Chrétien ◽  
M. Lis
Keyword(s):  
Methyl Ester ◽  
Coupling Agent ◽  
Lipolytic Activity ◽  
Biological Activities ◽  
Water Soluble ◽  
Carboxyl Groups ◽  
Glycine Methyl Ester

The carboxyl groups of sheep adrenocorticotropic and beta-lipotropic hormones (ACTH and beta-LPH) were modified by glycine methyl ester and taurine using a water-soluble carbodiimide as a coupling agent. The biological activities of these derivatives were measured and compared with those of the native hormones. With ACTH, the lipolytic activity is almost unaffected although the adrenocorticotropic activity is completely destroyed. LPH partially looses its lipolytic activity.

scholarly journals Synthesis and application of chemically reactive proteins by the reversible modification of protein amino groups with exo-cis-3,6-endo-epoxy-4,5-cis-epoxyhexahydrophthalic anhydride

1982 ◽  
Vol 203 (2) ◽  
pp. 345-350 ◽  
Author(s):  
R Schäfer
Keyword(s):  
Complete Recovery ◽  
Specific Protein ◽  
Enzymic Activity ◽  
Water Soluble ◽  
Organic Substrates ◽  
Amino Groups ◽  
Hydrophobic Membrane ◽  
Free Protein ◽  
Lysine Residues ◽  
Epoxy Groups

The reversible reaction of exo-cis-3,6-endo-epoxy-4,5-cis-epoxyhexahydrophthalic anhydride (EEHPA) with free protein amino groups is described. The free protein amino groups of lysozyme can be completely blocked through the reaction of the anhydride EEHPA. The chemically less reactive epoxy groups in EEHPA-modified lysozyme remain intact during modification of the protein and can be used for many subsequent chemical reactions. Hydrolysis of the modified inactive lysozyme at pH 2.5 results in deblocking and almost complete recovery of the enzymic activity of the protein. The epoxy groups in EEHPA-modified proteins have a great many potential uses: disaggregation of supramolecular structures, conversion of hydrophobic membrane proteins or tryptic peptides into water-soluble coloured proteins or peptides, inhibition of tryptic cleavage at lysine residues, synthesis of chemically reactive proteins or enzymes for affinity chromatography or immobilized-enzyme technology, two-dimensional separation techniques for complex protein mixtures, detection of specific protein-binding sites for organic substrates or tumour diagnostics, synthesis of defined artificial glycoproteins for biophysical and cytochemical studies and chemical synthesis of radioactively labelled proteins.

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