Occurrence of an Affinity Site apart from the Active Site on the Raw-Starch-Digesting but Non-Raw-Starch-Adsorbable Bacillus subtilis 65 α-Amylase

α-Cyclodextrin specifically inhibited raw starch digestion by Bacillus subtilis 65 α-amylase. The raw starch digestibility and α-cyclodextrin-Sepharose 6B adsorbability of this α-amylase were simultaneously lost when the specific domain corresponding to the affinity site essential for raw starch digestion was deleted by proteolysis. Occurrence of the affinity site on raw-starch-digesting enzymes was proven also with bacterial amylase

Estrogenic Prenylated Flavonoids in <i>Sophora flavescens</i>

Sophora flavescens is a medicinal herb distributed widely in Japan and it has been used to treat various diseases and symptoms. To explore its pharmacological use, we examined the estrogenic activity of four prenylated flavonoids, namely kurarinone, kushenols A and I, and sophoraflavanone G, which are characterized by the lavandulyl group at position 8 of ring A, but have variations in the hydroxyl group at positions 3 (ring C), 5 (ring A) and 4’ (ring B). These prenylated flavonoids were examined via cell proliferation assays using sulforhodamine B, Western blotting, and RT-PCR, corresponding to cell, protein, and transcription assays, respectively, based on estrogen action mechanisms. All the assays employed here found weak but clear estrogenic activities for the prenylated flavonoids examined. Furthermore, the activities were inhibited by an estrogen receptor antagonist, suggesting that the activities were likely being mediated by the estrogen receptors. However, there were differences in the activity, attributable to the hydroxyl group at position 4’, which is absent in kushenol A. While the estrogenic activity of kurarinone and sophoraflavanone G has been reported before, to the best of our knowledge, there are no such reports on kushenols A and I. Therefore, this study represents the first report of their estrogenic activity

Growth Inhibition of Escherichia coli by Overexpression of Rat Perchloric Acid-soluble Protein

Perchloric acid-soluble protein (PSP) and its highly homologous proteins are conserved among plants, archaea, bacteria, and eucarya. Although several functions of PSP have been elucidated in various species, the main role of PSP remains unclear. We previously demonstrated that PSP suppressed cell proliferation in mammalian cell lines. However, to the best of our knowledge, there are no reports on its function in other species. In this study, we investigated cell growth suppression of E. coli by rat PSP (rPSP). rPSP-His, GST-rPSP, or a GST expression vector were transformed into E. coli DH5α (DE3) cells, and expressions of recombinants were induced by IPTG. All recombinant expressions were detected in the presence of > 0.05 mM IPTG. The growth of transformed E. coli cells was suppressed by rPSP-His and GST-rPSP. Suppression ability of rPSP-His was stronger than that of GST-rPSP

Structural and Mechanistic Exploration of Acid Resistance: Kinetic Stability Facilitates Evolution of Extremophilic Behavior

Proteins from extremophilic organisms have evolved to remain stable and functional under extra-Abbreviations used: αLP, α-lytic protease; AEBSF