Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have used the yeast estrogen (YES) consisting of the human estrogen receptor and a reporter containing two estrogen response elements linked to the lacZ gene to evaluate the interaction between ovarian, phyto-, and synthetic estrogens with extracellular binding proteins. YES was incubated with charcoal-stripped human serum, human sex hormone-binding globulin, or human alpha-fetoprotein in the presence of concentrations of various estrogens that induced a 100% estrogenic response, as measured by beta-galactosidase activity. The activity of estradiol and coumestrol, a phytoestrogen, was reduced 75% with physiological levels of serum, sex hormone-binding globulin, or alpha-fetoprotein. The beta-galactosidase activity of genistein, another phytoestrogen, also decreased with extracellular proteins but to a lower extent than estradiol. In contrast, the activity of the synthetic estrogens diethylstilbestrol, kepone, and p,'p-DDD was only minimally reduced with extracellular proteins. These results indicate a potential fundamental difference in the interaction of estrogens from diverse sources with extracellular binding proteins. This suggests that the capacity for various estrogens to induce estrogen-associated responses is in part regulated by their affinity for extracellular bindings proteins.
 ...
PMID:Differential interaction of natural and synthetic estrogens with extracellular binding proteins in a yeast estrogen screen. 891 58

A complementary recognition pair of a short-peptide tag and a small molecular probe is a versatile molecular tool for protein detection, handling, and purification, and so forth. In this manuscript, we report that the binuclear Ni(II)-DpaTyr (DpaTyr=bis((dipicolylamino)methyl)tyrosine) complex serves as a strong binding probe for an oligo-aspartate tag tethered to a protein. Among various binuclear metal complexes of M-DpaTyr (M=Zn(II), Ni(II), Mn(II), Cu(II), Cd(II), Co(III), and Fe(III)), we have found that Ni(II)-DpaTyr (1-2Ni(II)) displays a strong-binding affinity (apparent binding constant: K(app) approximately 10(5) M(-1)) for an oligo-aspartate peptide under neutral aqueous conditions (50 mM HEPES, 100 mM NaCl, pH 7.2). Detailed isothermal-titration calorimetry (ITC) studies reveal that the tri-aspartate D3-tag (DDD) is an optimal sequence recognized by 1-2Ni(II) in a 1:1 binding stoichiometry. On the other hand, other metal complexes of DpaTyr, except for Ni(II)- and Zn(II)-DpaTyr, show a negligible binding affinity for the oligo-aspartate peptide. The binding affinity was greatly enhanced in the pair between the dimer of Ni(II)-DpaTyr and the repeated D3 tag peptide (D3x2), such as DDDXXDDD, on the basis of the multivalent coordination interaction between them. Most notably, a remarkably high-binding affinity (K(app)=2x10(9) M(-1)) was achieved between the Ni(II)-DpaTyr dimer 4-4Ni(II) and the D3x2 tag peptide (DDDNGDDD). This affinity is approximately 100-fold stronger than that observed in the binding pair of the Zn(II)-DpaTyr (4-4Zn(II)) and the D4x2 tag (DDDDGDDDD), a useful tag-probe pair previously reported by us. The recognition pair of the Ni(II)-DpaTyr probe and the D3x2 tag can also work effectively on a protein surface, that is, 4-4Ni(II) is strongly bound to the FKBP12 protein tethered with the D3x2 tag (DDDNGDDD) with a large K(app) value of 5x10(8) M(-1). Taking advantage of the strong-binding affinity, this pair was successfully applied to the selective inactivation of the tag-fused beta-galactosidase by using the chromophore-assisted light inactivation (CALI) technique under crude conditions, such as cell lysate.
 ...
PMID:Binuclear Ni(II)-DpaTyr complex as a high affinity probe for an oligo-aspartate Tag tethered to proteins. 2014 69