(S)-Styryl-α-alanine Used To Probe the Intermolecular Mechanism of an Intramolecular MIO-Aminomutase

Biochemistry ◽  
2011 ◽  
Vol 50 (46) ◽  
pp. 10082-10090 ◽  
Author(s):  
Udayanga Wanninayake ◽  
Yvonne DePorre ◽  
Mark Ondari ◽  
Kevin D. Walker
Keyword(s):  
Intermolecular Mechanism

Ligand-induced phosphorylation of the colony-stimulating factor 1 receptor can occur through an intermolecular reaction that triggers receptor down modulation

1990 ◽  
Vol 10 (4) ◽  
pp. 1664-1671
Author(s):  
M Ohtsuka ◽  
M F Roussel ◽  
C J Sherr ◽  
J R Downing
Keyword(s):  
Colony Stimulating Factor ◽  
Intact Cells ◽  
Atp Binding Site ◽  
Truncation Mutant ◽  
Intermolecular Mechanism ◽  
Carboxy Terminal ◽  
Lysine Substitution ◽  
Stimulating Factor

Ligand-induced tyrosine phosphorylation of the human colony-stimulating factor 1 receptor (CSF-1R) could involve either an intra- or intermolecular mechanism. We therefore examined the ability of a CSF-1R carboxy-terminal truncation mutant to phosphorylate a kinase-defective receptor, CSF-1R[met 616], that contains a methionine-for-lysine substitution at its ATP-binding site. By using an antipeptide serum that specifically reacts with epitopes deleted from the enzymatically competent truncation mutant, cross-phosphorylation of CSF-1R[met 616] on tyrosine was demonstrated, both in immune-complex kinase reactions and in intact cells stimulated with CSF-1. Both in vitro and in vivo, CSF-1R[met 616] was phosphorylated on tryptic peptides identical to those derived from wild-type CSF-1R, suggesting that receptor phosphorylation on tyrosine can proceed via an intermolecular interaction between receptor monomers. When expressed alone, CSF-1R[met 616] did not undergo ligand-induced down modulation, but its phosphorylation in cells coexpressing the kinase-active truncation mutant accelerated its degradation.

The Mechanisms of Racemization of the 2,2'-Bipyridinebis-(1,10-phenanthroline) nickel(II) Ion and the 1,10-Phenanthrolinebis-(2,2'-bipyridine)-nickel(II) Ion

1963 ◽  
Vol 16 (1) ◽  
pp. 51 ◽  
Author(s):  
JA Broomhead ◽  
FP Dwyer
Keyword(s):  
Acid Solution ◽  
Organic Solvents ◽  
Intermolecular Mechanism ◽  
Basic Solutions ◽  
Bipyridine Ligand

The rates of racemization of the 1,10-phenanthrolinebis-(2,2'-bipyridine)nickel(II) ion and the 2,2'-bipyridinebis-(1,10-phenanthroline)nickel(II) ion have been measured in neutral, acid, and basic solutions as well as in organic solvents. Comparison of the rates in acid solution with the corresponding rates of dissociation has shown that racemization takes place by means of an intermolecular mechanism with the loss of one bipyridine ligand. Increased racemization rates in the presence of acids, bases, and specific ions such as NO2-;, Cl-, Br- have been accounted for by the same mechanism.

scholarly journals SCF E3-Mediated Autoubiquitination Negatively Regulates Activity of Cdc34 E2 but Plays a Nonessential Role in the Catalytic Cycle In Vitro and In Vivo

2007 ◽  
Vol 27 (16) ◽  
pp. 5860-5870 ◽  
Author(s):  
K. Matthew Scaglione ◽  
Parmil K. Bansal ◽  
Andrew E. Deffenbaugh ◽  
Alexi Kiss ◽  
Johnnie M. Moore ◽  
...  
Keyword(s):  
Catalytic Cycle ◽  
In Vitro Experiments ◽  
Unknown Mechanism ◽  
Mutant Proteins ◽  
Functional Consequence ◽  
Intermolecular Mechanism ◽  
Striking Contrast ◽  
Stimulation Of

ABSTRACT One of the several still unexplained aspects of the mechanism by which the Cdc34/SCF RING-type ubiquitin ligases work is the marked stimulation of Cdc34 autoubiquitination, a phenomenon of unknown mechanism and significance. In in vitro experiments with single-lysine-containing Cdc34 mutant proteins of Saccharomyces cerevisiae, we found that the SCF-mediated stimulation of autoubiquitination is limited to specific N-terminal lysines modified via an intermolecular mechanism. In a striking contrast, SCF quenches autoubiquitination of C-terminal lysines catalyzed in an intramolecular manner. Unlike autoubiquitination of the C-terminal lysines, which has no functional consequence, autoubiquitination of the N-terminal lysines inhibits Cdc34. This autoinhibitory mechanism plays a nonessential role in the catalytic cycle, as the lysineless K0Cdc34ΔC is indistinguishable from Cdc34ΔC in ubiquitination of the prototype SCFCdc4 substrate Sic1 in vitro, and replacement of the CDC34 gene with either the K0 cdc34 ΔC or the cdc34 ΔC allele in yeast has no cell cycle phenotype. We discuss the implications of these findings for the mechanism of Cdc34 function with SCF.

scholarly journals Ligand-induced phosphorylation of the colony-stimulating factor 1 receptor can occur through an intermolecular reaction that triggers receptor down modulation.

1990 ◽  
Vol 10 (4) ◽  
pp. 1664-1671 ◽  
Author(s):  
M Ohtsuka ◽  
M F Roussel ◽  
C J Sherr ◽  
J R Downing
Keyword(s):  
Colony Stimulating Factor ◽  
Intact Cells ◽  
Atp Binding Site ◽  
Truncation Mutant ◽  
Intermolecular Mechanism ◽  
Carboxy Terminal ◽  
Lysine Substitution ◽  
Stimulating Factor

Ligand-induced tyrosine phosphorylation of the human colony-stimulating factor 1 receptor (CSF-1R) could involve either an intra- or intermolecular mechanism. We therefore examined the ability of a CSF-1R carboxy-terminal truncation mutant to phosphorylate a kinase-defective receptor, CSF-1R[met 616], that contains a methionine-for-lysine substitution at its ATP-binding site. By using an antipeptide serum that specifically reacts with epitopes deleted from the enzymatically competent truncation mutant, cross-phosphorylation of CSF-1R[met 616] on tyrosine was demonstrated, both in immune-complex kinase reactions and in intact cells stimulated with CSF-1. Both in vitro and in vivo, CSF-1R[met 616] was phosphorylated on tryptic peptides identical to those derived from wild-type CSF-1R, suggesting that receptor phosphorylation on tyrosine can proceed via an intermolecular interaction between receptor monomers. When expressed alone, CSF-1R[met 616] did not undergo ligand-induced down modulation, but its phosphorylation in cells coexpressing the kinase-active truncation mutant accelerated its degradation.

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