Kinetics of chemical modification of arginine and lysine residues in calf thymus histone H1

Biopolymers ◽  
1981 ◽  
Vol 20 (6) ◽  
pp. 1103-1112 ◽  
Author(s):  
Kazuei Mita ◽  
Sachiko Ichimura ◽  
Mitsuo Zama ◽  
Koei Hamana
Keyword(s):  
Chemical Modification ◽  
Histone H1 ◽  
Calf Thymus ◽  
Lysine Residues ◽  
Kinetics Of

scholarly journals Positive co-operative binding at two weak lysine-binding sites governs the Glu-plasminogen conformational change

1992 ◽  
Vol 285 (2) ◽  
pp. 419-425 ◽  
Author(s):  
U Christensen ◽  
L Mølgaard
Keyword(s):  
Ligand Binding ◽  
Binding Site ◽  
Conformational Change ◽  
Conformational Changes ◽  
Binding Sites ◽  
High Specificity ◽  
Stopped Flow ◽  
Protein Fluorescence ◽  
Lysine Residues ◽  
Kinetics Of

The kinetics of a series of Glu-plasminogen ligand-binding processes were investigated at pH 7.8 and 25 degrees C (in 0.1 M-NaCl). The ligands include compounds analogous to C-terminal lysine residues and to normal lysine residues. Changes of the Glu-plasminogen protein fluorescence were measured in a stopped-flow instrument as a function of time after rapid mixing of Glu-plasminogen and ligand at various concentrations. Large positive fluorescence changes (approximately 10%) accompany the ligand-induced conformational changes of Glu-plasminogen resulting from binding at weak lysine-binding sites. Detailed studies of the concentration-dependencies of the equilibrium signals and the rate constants of the process induced by various ligands showed the conformational change to involve two sites in a concerted positive co-operative process with three steps: (i) binding of a ligand at a very weak lysine-binding site that preferentially, but not exclusively, binds C-terminal-type lysine ligands, (ii) the rate-determining actual-conformational-change step and (iii) binding of one more lysine ligand at a second weak lysine-binding site that then binds the ligand more tightly. Further, totally independent initial small negative fluorescence changes (approximately 2-4%) corresponding to binding at the strong lysine-binding site of kringle 1 [Sottrup-Jensen, Claeys, Zajdel, Petersen & Magnusson (1978) Prog. Chem. Fibrinolysis Thrombolysis 3, 191-209] were observed for the C-terminal-type ligands. The finding that the conformational change in Glu-plasminogen involves two weak lysine-binding sites indicates that the effect cannot be assigned to any single kringle and that the problem of whether kringle 4 or kringle 5 is responsible for the process resolves itself. Probably kringle 4 and 5 are both participating. The involvement of two lysine binding-sites further makes the high specificity of Glu-plasminogen effectors more conceivable.

scholarly journals The pKa of the catalytic histidine residue of chloramphenicol acetyltransferase

1993 ◽  
Vol 290 (1) ◽  
pp. 15-19 ◽  
Author(s):  
A Lewendon ◽  
W V Shaw
Keyword(s):  
Chemical Modification ◽  
Ph Dependence ◽  
Thiol Group ◽  
Chloramphenicol Acetyltransferase ◽  
Histidine Residue ◽  
Pka Values ◽  
Primary Hydroxy Group ◽  
Pka Value ◽  
Catalytic Role ◽  
Kinetics Of

A catalytically essential histidine residue (His-195) of chloramphenicol acetyltransferase (CAT) acts as a general base in catalysis, abstracting a proton from the primary hydroxy group of chloramphenicol. The pKa of His-195 has been determined from the pH-dependence of chemical modification. Both methyl 4-nitrobenzenesulphonate and iodoacetamide inactivate CAT by irreversible modification of His-195. The kinetics of inactivation by methyl 4-nitrobenzenesulphonate are pseudo-first-order, and the pH-dependence of inactivation yields a pKa value of 6.60. Iodoacetamide inactivation proceeds with second-order kinetics and a pKa value of 6.80. An alternative site of modification at the active site of CAT is the thiol group of Cys-31, a residue which has no catalytic role. On replacement of Cys-31 with alanine (Ala-31 CAT), the pH-dependence of iodoacetamide inactivation gives a pKa value of 6.66. The pKa values derived from chemical-modification experiments directed at His-195 are in agreement with the pKa values of 6.62 and 6.61 determined for wild-type and Ala-31 CAT respectively from the pH-dependence of kcat/Km.

Kinetics of Nucleosomal Histone H1 Hyper(ADP-Ribosylation) and Polynucleosomes Relaxation

1985 ◽  
pp. 197-206 ◽  
Author(s):  
Claude Niedergang ◽  
Marie-Elisabeth Ittel ◽  
Gilbert De Murcia ◽  
Jean Pouyet ◽  
Paul Mandel
Keyword(s):  
Histone H1 ◽  
Adp Ribosylation ◽  
Kinetics Of ◽  
Nucleosomal Histone

scholarly journals Chemically enucleated mouse oocytes: ultrastructure and kinetics of histone H1 kinase activity

1998 ◽  
Vol 38 (6) ◽  
pp. 643-651 ◽  
Author(s):  
Lenka Kárníková ◽  
Mária Horská ◽  
Milan Tománek ◽  
Jiří Kaňka ◽  
František Urban ◽  
...  
Keyword(s):  
Kinase Activity ◽  
Histone H1 ◽  
Mouse Oocytes ◽  
Kinetics Of

Chemical modification of histidine and lysine residues of crotoxin

FEBS Letters ◽  
1978 ◽  
Vol 87 (2) ◽  
pp. 291-296 ◽  
Author(s):  
Tzyy-Wen Jeng ◽  
H. Fraenkel-Conrat
Keyword(s):  
Chemical Modification ◽  
Lysine Residues

scholarly journals The binding of adenosine(5′)tetraphospho(5′)adenosine to calf thymus histones measured by non-equilibrium dialysis

1987 ◽  
Vol 246 (3) ◽  
pp. 681-686 ◽  
Author(s):  
G Just ◽  
E Holler
Keyword(s):  
Ionic Strength ◽  
Dissociation Constants ◽  
Equilibrium Dialysis ◽  
Physiological Saline ◽  
Histone H1 ◽  
The Other ◽  
Competition Assay ◽  
Calf Thymus ◽  
Non Equilibrium

Binding of adenosine(5′)tetraphospho(5′)adenosine (Ap4A) to histones of calf thymus was investigated by non-equilibrium dialysis. Histone H1 interacts with the dinucleotide via two strong sites and competes with Mg2+ ions. Intrinsic dissociation constants were 1.6 +/- 0.1 microM and 11 +/- 1 microM for zero and 0.4 mm-Mg2+ concentration respectively. Binding of poly(dT) and of other nucleotides to histone H1 was measured in an [3H]Ap4A-competition assay. The tendency to form complexes among nucleotides was highest for bisnucleoside tetraphosphates and decreased in the order poly(dT) greater than or equal to Ap4A approximately Gp4G greater than Ap4 much greater than Ap3A approximately Ap5A greater than or equal to ATP, GTP and dTTP. The co-ordination complex derived from Ap4A and cis-diammine-dichloroplatinum(II) was not reactive. The other histones of calf thymus also bound Ap4A with affinities decreasing in the order H4 approximately H3 greater than H1 greater than H2b greater than H2a. Ap4A stimulated the exchange of histone H1 between nucleosomes, but this effect was referred to ionic strength. It did not bind to assembled nucleosomes. Binding of Ap4A to histone H1 was decreased by salt (NaCl). At physiological saline concentration the value of the dissociation constant is commensurable with the value of the Ap4A concentration in the nucleus and thus indicative of complex-formation in vivo.

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